Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| higher frequency of leishmania major-specific l3t4+ t cells in susceptible balb/c as compared with resistant cba mice. | in previous studies, we reported that a) the adoptive transfer of parasite-specific l3t4+ t cells enhanced rather than inhibited the development of lesions induced by leishmania major in normal balb/c mice, and b) the depletion in vivo of l3t4+ t cells by administration of anti-l3t4 monoclonal antibody reversed the susceptibility of balb/c mice to l. major. to further assess the role of specific l3t4+ t cells in the development of lesions induced by l. major in balb/c mice, the frequency of para ... | 1986 | 2418115 |
| antigen recognition by effector t cells in antileishmanial defense. | we have observed that t cells (ly1+2-) from draining lymph nodes of mice that have footpad infections with leishmania major activate macrophages for antileishmanial effects in vitro in an apparently contact-dependent, noncytotoxic manner. the nature of antigenic specificity in this system was investigated. whereas lymphocytes sensitized to l. major induced antileishmanial effects in macrophages infected with l. major, lymphocytes sensitized to listeria monocytogenes were ineffective. when macrop ... | 1985 | 2413143 |
| characterization of leishmania major antigen-liposomes that protect balb/c mice against cutaneous leishmaniasis. | leishmania major antigen-liposomes prepared as dehydration-rehydration vesicles (drv) and composed of equimolar amounts of l-alpha-distearoyl phosphatidylcholine and cholesterol confer high-level host-protective immunity against virulent homologous challenge to susceptible balb/c mice. physical and antigenic characterization of these protective liposomes is described. both empty and l. major antigen-drv were multilamellate and heterogeneous in size, ranging from 0.10 to 2.00 microns. although th ... | 1990 | 2401562 |
| leishmania infecting man and wild animals in saudi arabia. 7. partial protection of mice against leishmania major by prior infection with l. arabica. | a survey of inbred mouse strains showed that strain c3h/he was the most comparable to man in respect of its susceptibility to leishmania major and the subsequent healing of lesions produced by this organism. l. arabica proved to have a lower virulence than l. major and prior inoculation with the former resulted in a decrease of the lesion sizes following subsequent l. major challenge. moreover, l. major lesions that did develop in mice previously inoculated with l. arabica generally healed faste ... | 1990 | 2389313 |
| experimental transmission of leishmania major to vervet monkeys (cercopithecus aethiops) by bites of phlebotomus duboscqi (diptera: psychodidae). | experimental transmission of leishmania major to vervet monkeys (cercopithecus aethiops) was accomplished by bites of phlebotomus duboscqi sandflies. three-day-old, laboratory-reared p. duboscqi were fed on leishmanial lesions on hamsters infected with l. major. the flies were re-fed on monkeys 10 d after infection. five adult male vervet monkeys were used in concurrent transmission trials. two of the monkeys received subcutaneous inoculations with stationary-phase promastigotes (2 x 10(6) proma ... | 1990 | 2389312 |
| cyclosporin a treatment converts leishmania donovani-infected c57bl/10 (curing) mice to a noncuring phenotype. | cyclosporin a prevents visceralization of leishmania major infection of balb/c mice (n. c. behforouz, c. d. wenger, and b. a. mathison, j. immunol. 136:3067-3075, 1986; w. solbach, k. forberg, e. kammerer, c. bogdan, and m. rollinghoff, j. immunol. 134:702-707, 1986). we report that cyclosporin a exacerbates disseminated leishmaniasis caused by l. donovani in c57bl/10 mice. normal mice challenged with 5 x 10(6) amastigotes intravenously cleared the infection within several months by spontaneous ... | 1990 | 2387638 |
| leishmania major: inhibition of the chemiluminescent response of human polymorphonuclear leukocytes by promastigotes and their excreted factors. | the effect of various leishmanial preparations on the chemiluminescent response (cr) of human polymorphonuclear leukocytes (pmn) was studied. almost no cr was observed with pmn stimulated with either leishmania promastigotes or their excreted factors (efs). promastigotes added to pmn stimulated with phorbol myristate acetate (pma), at a proportion of 20 to 1, respectively inhibited approximately 80-83% of the cr activity. leishmanial promastigotes, whether live or dead, infective or non-infectiv ... | 1990 | 2385444 |
| development of leishmania major in phlebotomus duboscqi and sergentomyia schwetzi (diptera: psychodidae). | the extrinsic development of leishmania major was observed in 2 man-biting sand flies, phlebotomus duboscqi, a known vector, and sergentomyia schwetzi, an assumed non-vector. flies fed on a leishmanial lesion on the nose of a hamster were examined for infection at 0, 6, 12, 18, 24, 36, 48, and 60 hr and at approximately 24 hr intervals from day 3 to day 14 post-feeding. infection rates, determined by light microscopy, were 47% (n = 258) in p. duboscqi and 5% (n = 162) in s. schwetzi. transformat ... | 1990 | 2382763 |
| effect of leishmania major on human polymorphonuclear leucocyte function in vitro. | the effect of various antigens of leishmania major promastigotes on the function of human polymorphonuclear leucocytes (pmnls) was examined. different concentrations of l. major antigens were incubated with isolated pmnls for various periods and the respiratory burst was assessed by luminol-dependent chemiluminescence. all the leishmania antigens employed inhibited the pmnl respiratory burst by 35-64%. pmnl viability was not affected either by the concentrations or type of the parasite antigen. ... | 1990 | 2374156 |
| lipophosphoglycan expression and virulence in ricin-resistant variants of leishmania major. | lipophosphoglycan (lpg) of leishmania is a polymorphic molecule comprising an alkylglycerol anchor, a conserved oligosaccharide core and a species-specific polymer of oligosaccharide repeats jointed by phosphodiester bonds. this molecule, together with the membrane polypeptide gp63, has been implicated as a parasite receptor for host macrophages. to examine the role of lpg in parasite infectivity glycosylation variants of leishmania major were generated by chemical mutagenesis of a virulent clon ... | 1990 | 2362605 |
| evolution of nuclear dna and the occurrence of sequences related to new small chromosomal dnas in the trypanosomatid genus endotrypanum. | comparisons of nuclear dna restriction fragment patterns were used to examine the evolutionary relatedness among 17 strains previously identified as endotrypanum, a trypanosomatid parasite of sloths. fragments were obtained with 6 restriction enzymes and analyzed by southern blotting with hybridization probes from three loci. an estimate of the percent nucleotide sequence divergence among strains, delta, was calculated and used to construct molecular evolutionary trees. the 17 isolates fell into ... | 1990 | 2362601 |
| rapid quantitative method for measuring phagocytosis of leishmania promastigotes using a double radiolabelling method. | a double radiolabelling method is described for the measurement of phagocytosis of leishmania major promastigotes in cultures of murine resident peritoneal macrophages. l. major promastigotes were radiolabelled during exponential growth in rpmi supplemented with [125i]5-iodo-2-deoxyuridine. they were used to infect sodium [51cr]chromate-labelled macrophages. phagocytosis was evaluated by measuring the radioactivity of the 125iudr-labelled parasites detectable inside 51cr-labelled macrophages by ... | 1990 | 2358689 |
| macrophage killing of leishmania parasite in vivo is mediated by nitric oxide from l-arginine. | peritoneal macrophages from cba mice incubated with rifn-gamma are effective in killing the protozoal parasite leishmania major in vitro. this leishmanicidal activity can be completely inhibited by l-ng-monomethyl arginine (l-nmma), a specific inhibitor of the l-arginine:nitric oxide (no) pathway. the culture supernatants of macrophage activated by ifn-gamma contain increased levels of no2-, the production of which is inhibited by l-nmma, but not by its d-enantiomer. l. major promastigotes are k ... | 1990 | 2351828 |
| elemental composition of polyphosphate-containing vacuoles and cytoplasm of leishmania major. | leishmania major promastigotes contain electron-dense vacuoles. the elemental composition of these vacuoles and of the cytoplasm was measured by electron probe x-ray microanalysis, using rapid cryopreservation techniques to prevent alterations in composition due to diffusion. the electron-dense vacuoles are rich in p, presumably present as polyphosphate (poly p). mg is present at about 9 times its cytoplasmic level. there is sufficient mg to largely neutralize most of the negative charge of the ... | 1990 | 2348832 |
| isolation of genes showing increased or unique expression in the infective promastigotes of leishmania major. | the trypanosomatid parasite leishmania major is one of the principal causal agents of human cutaneous leishmaniasis. promastigotes grown in vitro undergo growth cycle-dependent differentiation, associated with morphological and biochemical changes, to produce forms which are infective to the mammalian host. by differentially screening a cdna library constructed from stage-specific mrna, we have isolated 4 clones encoding mrnas which show unique or elevated expression in the infective promastigot ... | 1990 | 2348831 |
| tumour necrosis factor (tnf alpha) in leishmaniasis. i. tnf alpha mediates host protection against cutaneous leishmaniasis. | genetically resistant cba mice developed significantly larger lesions to leishmania major infection when they were injected with rabbit anti-tumour necrosis factor (tnf)-specific antibodies compared to control mice injected with normal rabbit immunoglobulin. balb/c mice recovered from a previous infection following prophylactic sublethal irradiation also developed exacerbated lesions when treated with the anti-tnf antibody. injection of tnf into the lesion of infected cba mice significantly redu ... | 1990 | 2335376 |
| extracellular phosphorylation in the parasite, leishmania major. | intact promastigotes or cell-free extracts of the parasite leishmania major were labelled with adenosine 5'[gamma-32p]-triphosphate (atp). this resulted in the identification of eleven phosphoproteins. [gamma-32p]atp incorporation into endogenous and exogenous substrates was insensitive to most of the commonly used protein kinase inhibitors and activators indicating that the leishmanial enzyme(s) may represent a new class of kinase(s). in addition, exogenous substrate specificity was inconsisten ... | 1990 | 2334738 |
| genetic factors controlling susceptibility to leishmania major infection in the sand fly phlebotomus papatasi (diptera: psychodidae). | studies of the genetic factors controlling leishmania major infection in phlebotomus papatasi were carried out using 2 different sand fly lines: one highly susceptible and the other refractory to the parasite. l. major infection rates in both f1 and f2 generations from reciprocal crosses and in backcrosses between the parent lines showed that susceptibility and refractoriness of ph. papatasi to infection with l. major are controlled by less than 1 gene. neither susceptibility nor refractoriness ... | 1990 | 2331042 |
| selection of phlebotomus papatasi (diptera: psychodidae) lines susceptible and refractory to leishmania major infection. | variation in susceptibility to infection with cultured promastigotes of leishmania major was detected among 3 different geographic strains (israel, egypt, and india) of the sand fly phlebotomus papatasi. the israel strain showed the greatest susceptibility and was chosen for subsequent genetic selection experiments. after 13 generations of genetic selection in this strain, a stable refractory line was obtained in which only 7.5% of the insects could be infected. a highly susceptible line was als ... | 1990 | 2331041 |
| clonal heterogeneity in populations of leishmania major. | forty clones of leishmania major were derived by direct plating from lesions and from cultures of recent isolates, followed by plating as well as by additional limit dilution in some. the parental strains originated from and represented three geographical areas in each of which a distinct electrophoretic type of the enzyme 6-phosphogluconate dehydrogenase (6pgd) is found. each clone was characterized in terms of its virulence in sabra mice, morphology, serotype, enzyme electrophoretic profile ba ... | 1990 | 2329036 |
| t-cell hybridomas reveal two distinct mechanisms of antileishmanial defense. | using lymph node lymphocytes of leishmania major-infected mice, we constructed and cloned two t-cell hybridomas that could activate macrophages to exert antileishmanial defense in vitro. one clone, 1d5, produced lymphokines (including gamma interferon) that induced these effects. production of the macrophage-activating lymphokines and the protective effect of 1d5 were suppressed by the addition of cyclosporine a to cultures. the other clone, 1b6, produced no detectable macrophage-activating lymp ... | 1990 | 2323812 |
| parasite antigens recognized by patients with cutaneous leishmaniasis. | humoral and cell-mediated responses to crude and purified parasite antigens were examined in patients with active cutaneous leishmaniasis caused by leishmania major. the patients had serum antibody titres against parasite lysates ranging from 1/500 to 1/10,000 and recognized multiple components by western blotting with molecular weights between 5000 and greater than 200,000. several components, particularly at 5 and 50 kd, were recognized by most of the patients. the lymphoproliferative response ... | 1990 | 2323102 |
| leishmania gp63 molecule implicated in cellular adhesion lacks an arg-gly-asp sequence. | the parasitic protozoa leishmania are intracellular pathogens which enter host cells through largely undefined mechanisms. one molecule thought to play an important role in this process is gp63, the major glycoprotein on the surface of the infective promastigote form. we have cloned and analyzed the gp63 gene from leishmania chagasi, an etiologic agent of acute visceral leishmaniasis. the predicted amino acid sequence is highly homologous to that reported for leishmania major, with the exception ... | 1990 | 2320059 |
| nutrient broth for the cultivation of leishmania. | nutrient broth containing fetal calf serum was used successfully in isolating leishmania donovani from animals and cryopreserving leishmania major, leishmania donovani, and leishmania adleri. it also supported heavy growth of promastigotes of laboratory strains of l. donovani, l. major, l. adleri, and uncharacterized reptilian leishmania-like flagellates. | 1990 | 2319429 |
| size-conserved chromosomes and stability of molecular karyotype in cloned stocks of leishmania major. | molecular karyotypes for 5 stocks of leishmania major were derived by pulsed-field gradient gel electrophoresis and transverse alternating field electrophoresis. chromosome sizes obtained by the two methods agreed within less than or equal to 50kb. a set of 10 size-concordant chromosome bands between approx. 350-1000 kb was found in all stocks, plus a variable number of polymorphic chromosomes. cloned gene probes, and dna purified from individual chromosomes, hybridized to individual size-concor ... | 1990 | 2304489 |
| stable transfection of the human parasite leishmania major delineates a 30-kilobase region sufficient for extrachromosomal replication and expression. | to delineate segments of the genome of the human protozoan parasite leishmania major necessary for replication and expression, we developed a vector (pr-neo) which can be reproducibly introduced into l. major. this dna was derived from a 30-kilobase extrachromosomal amplified dna bearing the dihydrofolate reductase-thymidylate synthase gene, with the coding region for neomycin phosphotransferase substituted for that of dihydrofolate reductase-thymidylate synthase and a bacterial origin of replic ... | 1990 | 2304458 |
| protection against leishmania major in balb/c mice by adoptive transfer of a t cell clone recognizing a low molecular weight antigen released by promastigotes. | we have shown previously that balb/c mice can be protected against a fatal infection with leishmania major by adoptive transfer of a t cell line recognizing a protective soluble fraction (fraction 9) of promastigotes. we now describe the isolation and characterization of a t cell clone (9.1-2) that also transfers protective immunity against leishmania. after ag or mitogen stimulation, this clone secrets il-2 and ifn-gamma, but not il-4 or il-5. the clone preferentially recognizes l. major fracti ... | 1990 | 2295814 |
| characterization of two proteins from leishmania donovani and their use for vaccination against visceral leishmaniasis. | two proteins from leishmania donovani, dp72 and gp70-2, have been previously utilized to specifically serodiagnose patients with visceral leishmaniasis. the proteins were shown by elisa and western blotting with monoclonal and polyclonal antibodies to be present in both stages of the parasite. antibodies to gp70-2 recognize in promastigotes multiple discrete bands of similar m.w. which are common to several isolates of l. donovani. the total amount of ag and number of bands observed per isolate ... | 1990 | 2295807 |
| [the isoenzyme identification and pathogenic characteristics of clones of leishmania major, l. sp. nov. and l. gerbilli]. | using fonbrune's micromanipulators, 16 freshly obtained leishmania isolates (13 from r. opimus, 1 from p. papatasi, 2 from patients with skin leishmaniasis) have been cloned. 4 out of them were l. major isolates, 5 were l. sp. nov. isolates, 5 were mixed l. major and l. sp. nov. isolates and 1 was l. gerbilli isolate. 316 clones were identified using electrophoresis in polyacrylamide gel by 8 enzymes: pgi, pgm, 6-pgd, mdg, g-6-pgd, me, alat, asat--and tested for pathogenic activity on golden ham ... | 1990 | 2290404 |
| tumour necrosis factor (tnf-alpha) in leishmaniasis. ii. tnf-alpha-induced macrophage leishmanicidal activity is mediated by nitric oxide from l-arginine. | peritoneal macrophages from cba mice incubated with recombinant murine tumour necrosis factor (tnf-alpha) are effective in killing the protozoa parasite leishmania major in vitro. the leishmanicidal activity is directly correlated with the level of nitrite (no2-) in the culture supernatants. the killing of intracellular parasites can be completely inhibited by l-ng-monomethyl arginine (l-nmma), a specific inhibitor of the l-arginine:nitric oxide (no) pathway. the level of no2-, which is also a m ... | 1990 | 2279740 |
| sequence analysis and transcriptional activation of heat shock protein 83 of leishmania mexicana amazonensis. | changes in environmental temperature regulate the differential expression of genes during leishmania stage differentiation. therefore, molecular analysis of the heat shock proteins (hsps) in these parasites is of interest as a model for thermoregulation of gene expression. sequences of the hsp83 repetitive unit in the genome of leishmania mexicana amazonensis, including both the coding and intergenic regions, are described. the 5' boundary of the message was mapped by s1 analysis, to potential a ... | 1990 | 2270107 |
| released glycoconjugate of indigenous leishmania major enhances survival of a foreign l. major in phlebotomus papatasi. | the effect of leishmania glycoconjugate in the vector was investigated using phlebotomus papatasi artificially infected with a leishmania major strain that this vector does not transmit in nature. glycoconjugate of the vector-specific strain of l. major was added to the infective meals of some fly groups and the success of infections with or without this substance was compared 4 d later. in the absence of glycoconjugate the parasites survived in 15.6% of the flies, while the addition of 0.5 mg/m ... | 1990 | 2260168 |
| changes in the shape of leishmania major promastigotes in response to hexoses, proline, and hypo-osmotic stress. | leishmania major promastigotes in late-log phase are generally long and slender, and remain so during a 1 h incubation in buffer without exogenous substrate. when glucose, 2-deoxyglucose, fructose, mannose, or proline are added, the cells become shorter and more rounded. the shape change in response to glucose is complete within 20 min and is reversible upon incubating the cells without substrate. galactose, 3-o-methylglucose, 6-deoxyglucose, sucrose, maltose, ribose, glycerol, alanine, glutamat ... | 1990 | 2258829 |
| production of tumour necrosis factor during murine cutaneous leishmaniasis. | we have assessed the role of tumour necrosis factor-alpha (tnf) during cutaneous leishmaniasis and demonstrated that significant levels of tnf were released by spleen cells from infected mice after in vitro restimulation with leishmania major promastigotes. spleen cells from both genetically resistant and genetically susceptible mice were equally capable of producing tnf. after challenge with bacterial endotoxin, tnf activity could also be demonstrated in the serum of l. major-infected mice and ... | 1990 | 2255560 |
| susceptibility of inbred mice to leishmania major infection: genetic analysis of macrophage activation and innate resistance to disease in individual progeny of p/j (susceptible) and c3h/hen (resistant) mice. | we tested the possibility that two phenotypic traits, defective activation of macrophage antileishmanial activities and susceptibility to infection with leishmania major, were controlled by the same gene. we used p/j (susceptible) and c3h/hen (resistant) mice to breed f1, backcross (bx), and f2 mice that were tested individually for both traits, each of which is known to be controlled by a single autosomal gene. we found no correlation between the macrophage defect and cutaneous disease. there w ... | 1990 | 2254035 |
| structure of the lipophosphoglycan from leishmania major. | the major cell surface glycoconjugate of the parasitic protozoan leishmania major is a heterogeneous lipophosphoglycan. it has a tripartite structure, consisting of a phosphoglycan (mr 5,000-40,000), a variably phosphorylated hexasaccharide glycan core, and a lysoalkylphosphatidylinositol (lysoalkyl-pi) lipid anchor. the structures of the phosphoglycan and the hexasaccharide core were determined by monosaccharide analysis, methylation analysis, fast atom bombardment-mass spectrometry, one- and t ... | 1990 | 2246247 |
| nuclease mapping and dna sequence analysis of transcripts from the dihydrofolate reductase-thymidylate synthase (r) region of leishmania major. | trypanosomatid protozoan parasites utilize a number of nonstandard mechanisms in expressing their genes. to probe these phenomena in a genetically accessible system, we have mapped termini of eight transcripts arising from the amplified r region including the dhfr-ts gene of methotrexate-resistant leishmania major. poly(a)+ rnas transcribed from the dhfr-ts-coding strand exhibit features similar to those observed around other trypanosomatid protein-coding genes. these include close spacing, the ... | 1990 | 2243782 |
| gene replacement in parasitic protozoa. | trypanosomatid protozoa frequently cause severe diseases in humans. many molecules likely to have a role during the infectious cycle have been identified, yet proof of their function is often lacking. we describe studies in leishmania major of homologous gene targeting, a powerful method for testing gene function in other organisms. following introduction of a construct containing dihydrofolate reductase-thymidylate synthase (dhfr-ts) flanking sequences fused to neomycin phosphotransferase, 45% ... | 1990 | 2234081 |
| recurrent de novo appearance of small linear dnas in leishmania major and relationship to extra-chromosomal dnas in other species. | we have detected several new chromosome-sized dnas in lines derived from the lt252 isolate of leishmania major. these dnas appeared de novo in two clonal lines undergoing methotrexate (mtx) selection (clone 7-r50, clone 15-r50), in a stably mtx-resistant population reverting from mtx pressure (r1000-11-p55rev), and spontaneously during routine serial passage of the wild-type lt252 line in vitro (lt252+). no association of these new dnas with drug resistance was detected. the new chromosomes were ... | 1990 | 2233897 |
| cutaneous leishmaniasis serodiagnosis by immunoperoxidase assay. | immunoperoxidase assay was used for the determination of serum-specific anti-leishmanial igg antibodies in 65 patients with cutaneous leishmaniasis (cl), in 5 with visceral leishmaniasis (vl) and in 84 controls. a significant difference was observed between cl and vl sera and the control sera when either leishmania major, l. donovani or l. aethiopica intact promastigotes were used as antigens. cl patients showed similar activity against l. major and l. donovani antigen (titers 4-64 and less than ... | 1990 | 2228558 |
| leishmania major and l. donovani: a method for rapid purification of amastigotes. | 1990 | 2209791 | |
| leishmania major: expression and gene structure of the glycoprotein 63 molecule in virulent and avirulent clones and strains. | two leishmania membrane glycoconjugates, gp63 and lipophosphoglycan, have been implicated in parasite attachment and uptake into the host macrophage. moreover, recent data suggest that parasite virulence is associated with high expression of gp63. in this study we have surveyed gp63 gene copy number, in addition to the level of expression of gp63 mrna and protein in several leishmania major isolates, as well as virulent and avirulent strains and clones. the highest level of gp63 expression was f ... | 1990 | 2209787 |
| leishmania major: production of recombinant gp63, its antigenicity and immunogenicity in mice. | the mr 63,000 membrane polypeptide (gp63) is one of the leishmania receptors for host macrophages and has been shown to protect mice from infection. the gene encoding gp63, the major mr 63,000 surface glycoprotein of l. major promastigotes, has been expressed as a fusion protein with the enzyme glutathione s- transferase encoded by the parasitic helminth schistosoma japonicum. this fusion protein was recognized by polyclonal antibodies to the native leishmania gp63 polypeptide. the insoluble gp6 ... | 1990 | 2182337 |
| bifunctional thymidylate synthase-dihydrofolate reductase in protozoa. | protozoa contain thymidylate synthase (ts) and dihydrofolate reductase (dhfr) on the same polypeptide. in the bifunctional protein, the dhfr domain is on the amino terminus, ts is on the carboxyl terminus, and the two domains are separated by a junction peptide of varying size depending on the source. the native protein is composed of a dimer of two such subunits and is 110-140 kda. most studies of the bifunctional ts-dhfr have been performed with the protein from anti-folate resistant strains o ... | 1990 | 2180768 |
| thymidylate synthase-dihydrofolate reductase in protozoa. | in protozoa, thymidylate synthase (ts) and dihydrofolate reductase (dhfr) exist on the same polypeptide. the dhfr domain is on the amino terminus, ts is on the carboxy terminus, and the domains are separated by a junction peptide of varying size depending on the source. the native protein is a dimer of two such subunits and is 110-140 kda. most studies of bifunctional ts-dhfr have been performed with the protein from anti-folate resistant strains of leishmania major, which show amplification of ... | 1990 | 2178951 |
| developmental modification of the lipophosphoglycan from leishmania major promastigotes during metacyclogenesis. | lipophosphoglycan was isolated from the dividing, noninfective stage and from the nondividing metacyclic stage of leishmania major promastigotes. the lipophosphoglycans were characterized by sds-page and by chromatographic and quantitative analysis of phosphatidylinositol-specific phospholipase c- and mild acid-generated fragments. the results revealed two stage-specific structural differences: (i) an increase in size of the metacyclic form of the glycoconjugate due to an approximate doubling in ... | 1990 | 2176718 |
| tumor necrosis factor-alpha synergizes with ifn-gamma in mediating killing of leishmania major through the induction of nitric oxide. | cba mice develop cutaneous lesions when infected with leishmania major. the disease development was significantly reduced by injecting into the lesion a combination of rifn-gamma and rtnf-alpha. the doses of ifn-gamma and tnf-alpha used were suboptimal in that either cytokine alone did not have any effect. the therapeutic effect of ifn-gamma and tnf-alpha in vivo is reflected in their ability to activate macrophages to kill the intracellular parasites in vitro. the macrophage leishmanicidal acti ... | 1990 | 2175327 |
| genomic variation of trypanosoma cruzi: involvement of multicopy genes. | by using improved pulsed field gel conditions, the karyotypes of several strains of the protozoan parasite trypanosoma cruzi were analyzed and compared with those of leishmania major and two other members of the genus trypanosoma. there was no difference in chromosome migration patterns between different life cycle stages of the t. cruzi strains analyzed. however, the sizes and numbers of chromosomal bands varied considerably among t. cruzi strains. this karyotype variation among t. cruzi strain ... | 1990 | 2169461 |
| the glycoinositolphospholipid profiles of two leishmania major strains that differ in lipophosphoglycan expression. | the glycolipid profiles of two leishmania major strains which differ in their expression of the major glycoconjugate, lipophosphoglycan (lpg), have been compared. all the glycolipids in these strains belong to a class of glycoinositolphospholipids (gipls) which can be metabolically labelled with [3h]inositol and are sensitive to phosphatidylinositol-specific phospholipase c. the major glycolipids in the lpg-producing l. major strain v121 are tetraglycosyl phosphatidylinositol (gipl-1), pentaglyc ... | 1990 | 2157154 |
| serum resistance of metacyclic stage leishmania major promastigotes is due to release of c5b-9. | the mechanism of serum resistance for infective promastigotes of leishmania major was investigated. prior results suggested that the mechanism of resistance was mediated at a step after c3 deposition. equivalent amounts of c3b were deposited on serum-susceptible, noninfective promastigotes harvested from log stage cultures (log) and on c-resistant, infective, metacyclic promastigotes (mp) purified from stationary stage cultures. whereas binding of c9 to log was stable during incubation in serum, ... | 1990 | 2147941 |
| effect of glycolipids of leishmania parasites on human monocyte activity. inhibition by lipophosphoglycan. | lipophosphoglycan (lpg) and glycosyl phosphatidylinositol ag (gpi), are glycolipids present on the membrane of leishmania parasites. both glycolipids have been chemically characterized. lpg is a polysaccharide of repeating phosphorylated units linked to a phosphocarbohydrate core that is anchored to the membrane by lysoalkyl phosphatidylinositol (pi). the gpi are smaller glycolipids with a structure resembling the phosphocarbohydrate core of the lpg. they are anchored to the membrane by alkyl ac ... | 1990 | 2147940 |
| a repetitive peptide of leishmania can activate t helper type 2 cells and enhance disease progression. | leishmaniasis provides a biologically relevant model to analyze the heterogeneity of cd4+ t cells and may lead to answering the major question of the mechanism for the preferential induction of t helper type 1 (th1) and th2 cells. using synthetic peptides corresponding to the tandemly repeating regions of leishmania proteins, we have identified an epitope that can preferentially induce the disease-exacerbating th2 cells in susceptible balb/c mice. lymph node cells from balb/c mice immunized subc ... | 1990 | 2146362 |
| structure of the glycosyl-phosphatidylinositol membrane anchor of the leishmania major promastigote surface protease. | in common with many other plasma membrane glycoproteins of eukaryotic origin, the promastigote surface protease (psp) of the protozoan parasite leishmania contains a glycosyl-phosphatidylinositol (gpi) membrane anchor. the gpi anchor of leishmania major psp was purified following proteolysis of the psp and analyzed by two-dimensional 1h-1h nmr, compositional and methylation linkage analyses, chemical and enzymatic modifications, and amino acid sequencing. from these results, the structure of the ... | 1990 | 2145267 |
| oral salmonella typhimurium (aroa-) vaccine expressing a major leishmanial surface protein (gp63) preferentially induces t helper 1 cells and protective immunity against leishmaniasis. | the gp63 gene of leishmania major was transformed into the aroa- vaccine strain of salmonella typhimurium (sl3261). the construct (sl3261-gp63), which stably expresses the gp63 ag in vitro, was used to immunize cba mice by the oral route. spleen cells from mice inoculated with sl3261-gp63 developed antibody and proliferative t cell response to l. major. they did not express detectable delayed-type hypersensitivity reactivity. the activated t cells are mainly cd4+ and secrete il-2 and ifn-gamma b ... | 1990 | 2144549 |
| structures of the glycoinositolphospholipids from leishmania major. a family of novel galactofuranose-containing glycolipids. | structures of the major glycolipids isolated from the protozoan parasite leishmania major (strains v121 and lrc-l119), were elucidated by fast atom bombardment-mass spectrometry, two-dimensional proton nmr, methylation analysis, exoglycosidase digestions and mild acid hydrolysis. these glycolipids belong to a family of glycoinositolphospholipids (gipls), which contain 4-6 saccharide residues linked to alkylacylphosphatidylinositol (alkylacyl-pi) or lyso alkyl-pi. the general structure of the elu ... | 1990 | 2139661 |
| effects of culture age and hexoses on fatty acid oxidation by leishmania major. | the effect of culture age on the rate of oxidation of short-, medium, and long-chain fatty acids by leishmania major promastigotes was investigated. promastigotes from 5-day stationary phase cultures oxidized several saturated fatty acids about 3-to-4-fold faster than cells from late log phase cultures, but [10-14c]oleate was oxidized 9-fold faster. the increase in rate of oxidation was partially reversed within 5 h and almost completely reversed within 30 h after resuspending cells from a 5-day ... | 1990 | 2128337 |
| cellular mechanisms of nonspecific immunity to intracellular infection: cytokine-induced synthesis of toxic nitrogen oxides from l-arginine by macrophages and hepatocytes. | nitric oxide (no) produced by cytokine-treated macrophages and hepatocytes plays a vital role in protective host responses to infectious pathogens. no inhibits iron-sulfur-dependent enzymes involved in cellular respiration, energy production, and reproduction. synthesis of l-arginine-derived nitrite (no2-), the oxidative end product of no, directly correlates with intracellular killing of leishmania major, an obligate intracellular protozoan parasite of macrophages: the level of no2- production ... | 1990 | 2126524 |
| leishmania infecting man and wild animals in saudi arabia. 8. the influence of prior infection with leishmania arabica on challenge with l. major in man. | a clinical trial is described of an attempt to protect against leishmania major by prior vaccination with live l. arabica. after a single, previously leishmanin-negative, adult male volunteer was bitten by 8 phlebotomus papatasi infected with l. arabica, no infected lesions were observed. he remained leishmanin-negative and his lymphocytes reacted weakly to antigens of l. arabica or l. major. subsequently he and 3 other leishmanin-negative adult male volunteers were vaccinated with cultures cont ... | 1990 | 2126153 |
| development of a stable leishmania expression vector and application to the study of parasite surface antigen genes. | trypanosomatid protozoan parasites cause several important tropical diseases and have been a fertile ground for the discovery of molecular paradigms such as trans-splicing and rna editing. transfection-based methods for the study of these organisms have recently been developed, and we have now designed an expression vector, px, which contains only 2.3 kilobases of leishmania dna and can be stably transfected with high efficiency. genes encoding escherichia coli beta-galactosidase or a leishmania ... | 1990 | 2124701 |
| leishmania major amastigotes initiate the l-arginine-dependent killing mechanism in ifn-gamma-stimulated macrophages by induction of tumor necrosis factor-alpha. | macrophages exposed to ifn-gamma and infected with amastigotes of leishmania major develop the capacity to eliminate the intracellular pathogen. this antimicrobial activity of activated macrophages correlates with the initiation of nitrogen oxidation of l-arginine, yet other reports suggest that two signals are required for induction of this biochemical pathway for effector activity. in the present studies, macrophages treated with up to 100 u/ml ifn-gamma, or 100 ng lps, or 10(7) amastigotes pr ... | 1990 | 2124240 |
| patterns of cytokine secretion in murine leishmaniasis: correlation with disease progression or resolution. | susceptibility or resistance to infection with leishmania major correlates with the ability of mice to produce characteristic panels of lymphokines in response to the parasite. to investigate the role of antigen-presenting cells in this phenomenon, we developed a model system which used congenic (h-2d) susceptible and resistant mice. l. major-specific t cells were isolated from infected balb/c and b10.d2 mice, and the cells were restimulated in vitro on syngenic or congenic antigen-presenting ce ... | 1990 | 2123823 |
| il-2. a cofactor for induction of activated macrophage resistance to infection. | macrophages cultured with il-2 and ifn-gamma before exposure to microorganisms developed the ability to resist infection with the obligate intracellular parasite, leishmania major. the induction of this macrophage effector response was maximal by 6 to 8 h after lymphokine addition, and was independent of lymphokine treatment sequence. activation of macrophages for resistance to infection was the result of the direct action of il-2 and ifn-gamma on macrophages: the effector reaction was demonstra ... | 1990 | 2115543 |
| tumor necrosis factor-alpha in combination with interferon-gamma, but not with interleukin 4 activates murine macrophages for elimination of leishmania major amastigotes. | we have previously shown that during an infection with leishmania major, susceptible balb/c mice, as opposed to mice of a resistant strain (c57bl/6), are primed by lipopolysaccharide for the production of high levels of tumor necrosis factor-alpha (tnf-alpha) which is known to be a potent macrophage (m phi) stimulator in other parasitic diseases. in the present study we investigated whether tnf-alpha activates m phi for killing of l. major parasites. in the absence of interferon-gamma (ifn-gamma ... | 1990 | 2113475 |
| interleukin-2, anti-interleukin-2 receptor antibody, and activation of macrophages. | macrophages treated with ifn-gamma and il-2 before exposure to parasites develop the ability to resist infection with amastigotes of leishmania major. in this cooperative interaction of cytokines, il-2 can be replaced with any of several mab directed against the beta chain of the il-2 receptor, but not by antibodies to a number of other cell receptors or antigens. thus, antibodies to the il-2 receptor act as agonists of il-2 in the induction of a biologic activity in macrophages, and macrophages ... | 1990 | 2113433 |
| effects of oxygen concentration on the intermediary metabolism of leishmania major promastigotes. | leishmania major promastigotes grown in late log phase were incubated with glucose as sole exogenous carbon source in the presence of 5% co2 and the amounts of glucose consumed and of the major products formed--succinate, pyruvate, alanine, acetate, glycerol, and d-lactate--were measured as a function of po2. glucose consumption increased as po2 was lowered to 6% (a positive pasteur effect) and then declined to the same level at 95% n2 as at 95% o2. the production of d-lactate and of glycerol in ... | 1990 | 2108330 |
| cure of murine leishmaniasis with anti-interleukin 4 monoclonal antibody. evidence for a t cell-dependent, interferon gamma-independent mechanism. | balb/c mice infected with leishmania major develop fatal, progressive disease, despite an immune response characterized by expansion of cd4+ t cells in the draining lymph nodes. the immune response has been further characterized by a lack of ifn-gamma mrna, but increased il-4 mrna in lymphoid tissues, and striking elevation of serum ige. treatment of infected balb/c mice with rifn-gamma at doses shown to be beneficial in other protozoan infections was insufficient to ameliorate l. major infectio ... | 1990 | 2104918 |
| activated macrophages destroy intracellular leishmania major amastigotes by an l-arginine-dependent killing mechanism. | macrophages infected with amastigotes of leishmania major and treated with ifn-gamma in vitro develop potent antimicrobial activities that eliminate the intracellular parasite. this antileishmanial activity was suppressed in a dose dependent fashion by ng-monomethyl-l-arginine (ngmmla), a competitive inhibitor of nitrite, nitrate, nitric oxide and l-citrulline synthesis from l-arginine. excess l-arginine added to infected macrophage cultures reversed the inhibitory effects of ngmmla. addition of ... | 1990 | 2104889 |
| [ecoepidemiology of leishmaniasis in syria. 1. leishmania major yakimoff and schokhor (kinetoplastida-trypanosomatidae) infestation of psammomys obesus cretzschmar (rodentia-gerbillidae)]. | during an epidemiological survey of zoonotic cutaneous leishmaniasis in south-west syria, leishmania major zymodème mon-26 was isolated from a reservoir host, psammomys obesus terraesanctae (rodentia-gerbillidae). the abundance of this rodent, its close contact with infected villages and the high prevalence of the infection (63,1%) indicate that this is the main reservoir host of oriental sore in the semi desert area of this country. | 1990 | 2097930 |
| the characterization of leishmania major from phlebotomus papatasi (scopoli) caught in northern sinai, egypt. | 1990 | 2096507 | |
| expression of lpg and gp63 by different developmental stages of leishmania major in the sandfly phlebotomus papatasi. | development and forward migration of leishmania parasites in the sandfly gut is accompanied by morphological transformation to highly motile, non-dividing 'metacyclic' forms. previous studies in vitro have demonstrated that this metacyclogenesis is associated with developmentally regulated changes in expression of two major surface glycoconjugates of leishmania, the lipophosphoglycan (lpg) and the glycoprotein protease gp63. studies presented here are the first to examine in situ the changes in ... | 1990 | 2092290 |
| a case of diffuse cutaneous leishmaniasis due to leishmania major. | 1990 | 2091348 | |
| species- and infective stage-specific monoclonal antibodies to leishmania major produced by an in vitro immunization method. | monoclonal antibodies specific to the infective-stage promastigotes of leishmania major are needed for developing rapid diagnostic assays of infected sand flies. an in vitro immunization protocol was applied for the production of monoclonal antibodies using small amounts of l. major. infective-stage promastigotes were isolated from sand flies (phlebotomus papatasi) 7-10 days after infection and used as antigen for immunization. two weeks after a primary immunization, murine splenocytes were remo ... | 1990 | 2087235 |
| rapid shape change and release of ninhydrin-positive substances by leishmania major promastigotes in response to hypo-osmotic stress. | leishmania major promastigotes were grown to late-log phase and washed and resuspended in an isosmotic buffer. when osmolality was suddenly decreased by 50%, the cells rapidly became shorter and increased in width. cell volume, calculated assuming a prolate-ellipsoidal shape, increased 1.4 times after 1 min. over the next several minutes, the average length and width returned to control values while the volume returned to baseline, indicating the ability to regulate volume. concomitantly with th ... | 1990 | 2086781 |
| [susceptibility to and the characteristics of the course of experimental leishmaniasis in different species of mammals infected with leishmania major, l. turanica and l. gerbilli]. | 40 r. opimus and 69 m. libycus were infected and 59 human subjects were vaccinated in laboratory conditions. 13 cultures of 3 leishmania species and their mixtures were used. r. opimus turned to be sensitive to 3 leishmania species. leishmaniasis developed in the form of infiltrates irrespective of the leishmania species and pathogenic activity. ulceration and visceralization were always absent. differences in the duration of leishmania preservation in r. opimus have been noted. in l. major infe ... | 1991 | 2067472 |
| administration of beta-glucan following leishmania major infection suppresses disease progression in mice. | the potential of beta-glucan (glucan) to suppress the progression of lesions caused by virulent strains of leishmania major in genetically susceptible balb/c mice when administered post challenge was evaluated. glucan particles (glucanp) prepared from saccharomyces cerevisiae were injected i.v. at 7-day intervals starting 7 days after parasite challenge. four injections gave a more rapid and a higher extent of suppression than 1, 2 or 3 injections. mice receiving only parasites, a glucose soluti ... | 1991 | 2052403 |
| t-cell reactivity to purified lipophosphoglycan from leishmania major: a model for analysis of the cellular immune response to microbial carbohydrates. | the major macromolecule on the surface of leishmania major promastigotes is a lipophosphoglycan (lpg). this glycoconjugate plays a key role in determining infectivity and survival of parasites in the mammalian host cell. in addition, l. major lpg is able to induce a host-protective immune response. in this article, we summarise the evidence for recognition of highly purified lpg by t cells and we discuss the potential mechanisms of t-cell stimulation by this non-protein antigen. | 1991 | 2049034 |
| metacyclogenesis of leishmania spp: species-specific in vitro transformation, complement resistance, and cell surface carbohydrate and protein profiles. | metacyclic (stationary) and logarithmic (log) forms of promastigotes of leishmania donovani and leishmania major were characterized in several ways. the highly active metacyclic forms were larger with more protein and less carbohydrate. the flagellum increased in length 2.4 times in l. major as compared to 1.8 times in l. donovani. resistance to complement-mediated lysis by normal human serum of in vitro grown leishmania promastigotes was related to the species, the growth phase in culture, and ... | 1991 | 2040953 |
| biochemical characterization of leishmania major isolated from two egyptian patients. | leishmania major, the cause of human zoonotic cutaneous leishmaniasis, is a widely distributed parasite in the old world. here, we report the isoenzyme characterization of two human isolates obtained from egyptians who never travelled abroad. the two isolates were l. major equivalent to zymodene lond i. | 1991 | 2033298 |
| analysis of enhancing effect of sand fly saliva on leishmania infection in mice. | salivary gland lysates of the sand fly lutzomyia longipalpis markedly enhance the course of infection with leishmania major in mice. here we examine various parameters of this phenomenon. the exacerbative effect of l. longipalpis salivary gland lysates occurred in five different mouse strains; however, the character of the effect varied from one strain to another. consistent exacerbation of infection was achieved with as little as 1/10 of a gland. the exacerbative effect applied to more than one ... | 1991 | 2019430 |
| leishmania-sandfly interactions: an empirical field study. | phlebotomus papatasi is the sandfly vector of leishmania major in the jordan valley. the objective of this study was to characterize vector-parasite relations in an active zoonotic focus. seasonality and intensity of promastigote infection rates in female sandflies and the developmental stage of these hosts were established. on 153 trap-nights, 641 female p. papatasi were caught and examined. of these, 48 (7.4%, range 12.9-4.8%) were infected with l. major promastigotes. correlating the number o ... | 1991 | 2010872 |
| the comparative fine structure and surface glycoconjugate expression of three life stages of leishmania major. | the cellular ultrastructure and surface glycoconjugate expression of three life stages of leishmania major were compared. noninfective logarithmic phase promastigotes (lp) are immature cells bearing a thin cell coat, short flagellum, small and empty flagellar pocket, and a loose cytoplasm filled with profiles of er and large golgi complex. lp also contain subpopulations of maturing cells containing less er and golgi and synthesizing cytoplasmic granules of different size, number, and electron-de ... | 1991 | 2009923 |
| effect of hyper-osmotic stress on alanine content of leishmania major promastigotes. | earlier studies showed that leishmania major promastigotes are sensitive to osmotic conditions. a reduction in osmolality caused the cells to shorten and to rapidly release most of their large internal pool of alanine. in this study some effects of hyper-osmotic stress were examined. an increase in osmolality of the culture medium from 308 to 625 mosm/kg caused only a small decrease in growth rate. when cells grown in the usual culture medium (308 mosm/kg) were washed, resuspended in iso-osmotic ... | 1991 | 1997677 |
| identification and characterization of host-protective t-cell epitopes of a major surface glycoprotein (gp63) from leishmania major. | by using a series of overlapping synthetic peptides that cover more than 75% of the amino acid sequence of the major surface glycoprotein (gp63) from leishmania major, 11 t-cell epitopes in cba and balb/c mice have been identified. six of the peptides were recognized by t cells of cba mice recovered from l. major infection, while one was recognized by the t cells from balb/c mice recovered from the infection following sublethal doses of gamma-irradiation. lymph node cells from mice immunized wit ... | 1991 | 1997399 |
| synergy between activated leishmania major-specific cd4+ t lymphocytes and bone-marrow-derived cells in the exacerbation of murine cutaneous leishmaniasis. | mechanisms of exacerbation of murine cutaneous leishmaniasis mediated by leishmania major-specific cd4+ t lymphocytes were studied. using a limiting dilution assay for the quantification of leishmania parasites, the infected tissues (footpad) of lethally irradiated mice were found to contain tenfold less parasites at four days of infection than the footpads of infected unirradiated animals. injection of bone marrow cells depleted of t cells into irradiated mice at the site of infection led to an ... | 1990 | 1983098 |
| immunization of susceptible hosts with a soluble antigen fraction from leishmania major leads to aggravation of murine leishmaniasis mediated by cd4+ t cells. | this study was performed in order to define leishmania major antigens that function as disease-modulating immunogens in susceptible balb/c mice. a soluble leishmanial antigen preparation (s-sla) derived from highly infective stationary-phase l. major parasites was fractionated by preparative gel electrophoresis. in vitro, the low molecular mass fraction (less than 31 kda) of s-sla fraction d (fr d) was found to be a potent stimulator of l. major-specific th1 and th2 helper cell clones. in vivo, ... | 1990 | 1980108 |
| resistance to murine cutaneous leishmaniasis is mediated by th1 cells, but disease-promoting cd4+ cells are different from th2 cells. | a limiting dilution system has been used for quantitative analysis of antigen-reactive t cells producing interleukin (il)2, il4 and interferon (ifn)-gamma in the course of murine infection with leishmania major. the precursor frequencies of cd4+ cells with the potential for production of ifn-gamma, which has been associated with th1 cells, are much higher in resistant than in susceptible mice, whereas the reverse is found for cd4+ cells secreting il4 which have been classified as th2 cells. our ... | 1990 | 1976523 |
| leishmania major: nature of immunity induced by immunization with a mutagenized avirulent clone of the parasite in mice. | a chemically mutagenized avirulent form of leishmania major was used to immunize balb/c and c57b1/6 mice against challenge with virulent l. major. immunity was elicited when the avirulent parasite was injected intravenously or intraperitoneally, but not subcutaneously. in fact, the latter route of immunization sometimes resulted in exacerbation of a subsequent infection with virulent l. major. mice immunized with avirulent l. major developed upon challenge with virulent l. major cutaneous lesion ... | 1990 | 1972362 |
| cyclosporine-induced autoimmunity and immune hyperreactivity. | cyclosporine (cs) is a potent immunosuppressive agent which under some circumstances paradoxically augments dth responses, aggravates some autoimmune diseases, and induces specific forms of autoimmunity. the enhancement of dth and other immune responses is closely related to the timing of cs administration relative to immunization. cs inhibits il-2 production (and several other lymphokines) at a pretranscriptional level, but does not usually prevent the antigen-specific priming of t cells, such ... | 1991 | 1954315 |
| changes in intracellular levels of fructose 2,6-bisphosphate and several glycolytic intermediates in leishmania major promastigotes as a function of po2. | leishmania major promastigotes were grown to late log phase, washed and resuspended in hanks' balanced salt solution, and incubated with glucose at various po2s in the presence of 5% co2. samples were taken at times from 0-40 min and assayed for fructose 2,6-bisphosphate (fru(2,6)p2), glucose-6-phosphate (g6p), fructose-6-phosphate (f6p), phospho(enol)pyruvate (pep), and atp. at 95% o2 atp remained constant throughout the incubation. it did not decrease significantly at 10% o2, but decreased by ... | 1991 | 1944414 |
| populations of phlebotomus papatasi (diptera: psychodidae) and the risk of leishmania major transmission in three jordan valley habitats. | the abundance, population structure, and leishmania infection rates of phlebotomus papatasi were studied at two villages, a 10-yr old date plantation, and an undisturbed natural habitat in the jordan valley throughout one season. on 109 trap nights in the villages, 53 female and 61 male p. papatasi were caught, whereas in burrows in the natural and agriculturally modified habitat, greater than 3,500 sandflies were trapped on 157 trap nights. burrows in the data plantation produced larger numbers ... | 1991 | 1941907 |
| cytokine regulation of murine leishmaniasis: interleukin 4 is not sufficient to mediate progressive disease in resistant c57bl/6 mice. | neutralization of interleukin 4 (il-4) at the time of infection with leishmania major allowed susceptible balb/c mice to heal. recombinant il-4, however, had little effect on the course of l. major infection in resistant c57bl/6 mice, nor did coinfection with nippostrongylus brasiliensis, despite marked elevation of endogenous il-4 levels. | 1991 | 1937832 |
| expression of t-cell-associated serine proteinase 1 during murine leishmania major infection correlates with susceptibility to disease. | the expression of t-cell-associated serine proteinase 1 (mtsp-1) in vivo during leishmania major infection was analyzed in genetically resistant c57bl/6 mice and in genetically susceptible balb/c mice. using a monoclonal antibody as well as an rna probe specific for mtsp-1 to stain tissue sections, we found t cells expressing mtsp-1 in skin lesions and spleens of mice of both strains. in skin lesions, mtsp-1-positive t cells could be detected as early as 3 days after infection. most importantly, ... | 1991 | 1937831 |
| transmission and scanning em-immunogold labeling of leishmania major lipophosphoglycan in the sandfly phlebotomus papatasi. | previous studies using immunostaining and light microscopy demonstrated expression of leishmania major lipophosphoglycan (lpg) on parasites developing in the sandfly gut from 2 days post infection. by days 4 to 7 post infection, there appeared to be large amounts of parasite-free lpg deposited on/in the microvilli and epithelial cells lining the thoracic midgut, while forward migration of parasites and the morphological changes which accompany metacyclogenesis were associated with developmental ... | 1991 | 1935998 |
| concurrent infection with leishmania donovani and leishmania major in a kenyan patient: clinical description and parasite characterization. | leishmania isolates aspirated a few months apart from the spleen of an indigenous adult male kala-azar patient from baringo district, kenya, were biochemically characterized and compared. the patient lived within a dual focus of l. donovani kalazar and l. major cutaneous leishmaniasis. a primary leishmania isolate from splenic aspirates was cryopreserved (nlb-294). the patient was treated with sodium stibogluconate for kala-azar and discharged. three months later, he had clinical relapse and ret ... | 1991 | 1928563 |
| monoclonal antibodies that react with leishmania (viannia) naiffi. | monoclonal antibodies were raised against leishmania (viannia) naiffi, which recently has been characterized as a new species. balb/c mice were immunized with membrane-enriched fractions of a mixture of l. (v.) naiffi isolates. subsequent fusion of immunized splenocytes with ns-1 myeloma cells resulted in the production of 5 mabs (n1-n5). screening by elisa and indirect immunofluorescence against an extensive cross-panel of leishmania strains revealed that n3 was species-specific and could thus ... | 1991 | 1919913 |
| establishment of resistance to leishmania major infection in susceptible balb/c mice requires parasite-specific cd8+ t cells. | although cd4+ t cells are generally accepted to be responsible for the determination of resistance to infection in experimental murine cutaneous leishmaniasis, a contribution of cd8+ lymphocytes to immunity can be demonstrated under certain well-defined conditions. normally highly susceptible balb/c mice can be rendered resistant to infection with leishmania major promastigotes by a single injection of monoclonal anti-cd4 antibodies at the beginning of infection. mice treated in such a way can h ... | 1991 | 1909563 |
| simultaneous transient expression assays of the trypanosomatid parasite leishmania using beta-galactosidase and beta-glucuronidase as reporter enzymes. | we describe a transient transfection protocol for cultured leishmania major promastigotes, utilizing escherichia coli genes encoding beta-galactosidase and beta-glucuronidase inserted into an expression vector derived from the dihydrofolate reductase-thymidylate synthase locus. less than 0.1 pg of either reporter enzyme can be detected with a simple fluorimetric assay, and transfection of 10 micrograms of either reporter construct yields activities at least 100-fold over background. simultaneous ... | 1991 | 1908808 |
| production of interferon gamma, interleukin 2, interleukin 4, and interleukin 10 by cd4+ lymphocytes in vivo during healing and progressive murine leishmaniasis. | the expression of interleukin (il) 2, il-4, il-10, and interferon gamma (ifn-gamma) by lymphocyte subsets was examined during infection of resistant c57bl/6 and susceptible balb/c mice with the protozoan parasite leishmania major. cd4+ and cd8+ t lymphocytes and b lymphocytes were isolated from the lymph nodes draining infectious lesions, and their rna was examined for lymphokine transcripts. distinct patterns of cd4+ cell cytokine expression were apparent: c57bl/6 cd4+ cells contained ifn-gamma ... | 1991 | 1908085 |
| role of tumor necrosis factor in macrophage leishmanicidal activity in vitro and resistance to cutaneous leishmaniasis in vivo. | recombinant human tumor necrosis factor (tnf) and purified murine tnf were both able to activate macrophages to destroy intracellular leishmania major in vitro. in addition, parasitizing macrophages with l. major markedly increased the ability of the cells to produce tnf. finally, when mice were vaccinated with an avirulent form of l. major, the animals produced large amounts of tnf but no gamma interferon in response to infection with virulent l. major. treating these mice with a neutralizing a ... | 1991 | 1906844 |
| stable dna transfection of a wide range of trypanosomatids. | we have shown that the leishmania major transfection vector pr-neo (or derivatives thereof) can be introduced and stably maintained in four species complexes of pathogenic leishmania (l. tropica, l. mexicana, l. donovani, l. braziliensis), and the genera endotrypanum and crithidia; transfection of trypanosoma cruzi or trypanosoma brucei was not successful. quantitative plating assays showed that the transfection efficiencies were high in l. major and leishmania amazonensis (5x10(-5)/cell) and ab ... | 1991 | 1906580 |