Publications

v beta gene repertoires in t cells expanded in local self-healing and lethal systemic murine cutaneous leishmaniasis.	inbred mice infected with leishmania major promastigotes display two different courses of leishmaniasis: resistant strains develop self-healing local sores, while susceptible strains show progressive systemic disease with lethal outcome. resistance predominantly correlates with the production of t helper type 1 (th1) lymphokines and susceptibility with production of th2-type lymphokines. here, we analyzed whether this th phenotype difference correlates with expression of particular t cell recept ...	1994	7905419
cytokines in the differentiation of th1/th2 cd4+ subsets in leishmaniasis.	leishmania major infect only macrophages in the host, where they reside in endolysosomal compartments into which mhc class ii molecules co-localize. experimental infection in mice has provided a useful model for the differentiation of th1 cd4+ effector lymphocytes that are required for the generation of ifn-gamma that activates the macrophage to a microbicidal state. genetically susceptible balb/c mice aberrantly activate th2 cd4+ effector cells that are ineffective in arresting infection. incre ...	1993	7905485
[importance of the different t lymphocytes subsets in immunity of mice against an intracellular protozoan parasite: leishmania major].	the resolution of lesions in mice experimentally infected with l. major requires the expansion of cd4+ t cells specific for parasite antigens which release or express on their membranes lymphokines typical of those secreted by cd4+ th1 cells. these lymphokines activate macrophages containing l. major to a parasiticidal state through the production of molecules toxic for the parasite. the anti-leishmania effector function of parasite-specific cd4+ th1 cells was found dependent upon their fine spe ...	1993	7906028
cd4+ effector cells default to the th2 pathway in interferon gamma-deficient mice infected with leishmania major.	mice with homologous disruption of the interferon gamma (ifn-gamma) gene on the c57bl/6 background were infected with leishmania major and the immune response assessed. in contrast to wild-type or heterozygous knockout mice, deficient animals were unable to restrict growth of the parasite and suffered lethal infection over 6-8 wk. although wild-type and heterozygous littermates developed cd4+ cells that contained transcripts for ifn-gamma and lymphotoxin, typical of t helper type 1 (th1) cells, ...	1994	7908325
the major surface glycoprotein (gp63) from leishmania major and leishmania donovani cleaves cd4 molecules on human t cells.	the effect of leishmania major and l. donovani surface protease gp63 on surface markers on human t cells was studied using fluorescence-activated flow cytometry. purified gp63 (63,000 m.w. glycoprotein) at concentrations above 10 micrograms/ml completely inhibited binding of six different anti-cd4 abs to human t cells, whereas the binding of one ab, okt4, was not inhibited. heat inactivation of the protease before the incubation with cells abolished the effect on binding of anti-cd4 abs. cells i ...	1994	7908919
infection with leishmania major induces interleukin-12 production in vivo.	experimental infections of mice with the protozoan parasite leishmania major provide an excellent model for defining the conditions required for generation of cd4+ th1 and th2 cells in vivo. since interleukin-12 (il-12) has been implicated in the development of th1 cells, we investigated whether l. major stimulates il-12 production in vitro or in vivo. surprisingly, macrophages cultured in vitro failed to produce il-12 following l. major infection. in contrast, lymph node cells from c3h mice inf ...	1994	7916331
leishmania major: characterisation and expression of a cytoplasmic stress-related protein.	the dna sequence of a single-copy gene from leishmania major has been determined and shown to share sequence identity with eukaryotic heat shock protein-70-related genes. conserved features of the deduced open reading frame include amino acids implicated in atp binding and a putative calmodulin-binding domain. antibodies generated to the recombinant fusion protein recognise a 70-kda molecule of pi 6.0. this molecule is constitutively expressed and localises to the cytoplasm in all stages of the ...	1993	7916697
cutaneous leishmaniasis: co-ordinate expression of granzyme a and lymphokines by cd4+ t cells from susceptible mice.	we have recently demonstrated that the frequency of t cells expressing granzyme a is significantly higher in skin lesions and spleens of susceptible balb/c mice compared with resistant c57bl/6 mice infected with leishmania major, a cause of human cutaneous leishmaniasis. in the present study, we have performed in vitro studies to characterize the subpopulation, the antigen responsiveness and the lymphokine production pattern of granzyme a-expressing t cells in l. major-infected mice. using a lim ...	1994	7927497
recombinant soluble interleukin-4 (il-4) receptor acts as an antagonist of il-4 in murine cutaneous leishmaniasis.	this study was performed to evaluate the soluble interleukin-4 receptor (sil-4r) as a potential antagonist of interleukin-4 (il-4) in an infectious disease. it is shown that antigen-triggered proliferation and cytokine secretion of leishmania major-specific, cloned th2 cells in vitro can be inhibited dose dependently by recombinant murine, but not control human, sil-4r. in vivo, we found that endogenous synthesis of il-4 mrna is upregulated during the first week of infection, while an increase o ...	1994	7927664
stage-specific regulation of protein phosphorylation in leishmania major.	we investigated whether there are changes in protein phosphorylation or protein kinase activities during the life cycle of leishmania major. using a kinase renaturation assay, we detected several leishmanial kinases at each stage of the life cycle. in particular we identified a 50-kda kinase that is active in procyclic and metacyclic parasites but is inactive in amastigotes. an in vitro phosphorylation assay demonstrated that the pattern of serine and threonine phosphorylated proteins was regula ...	1994	7935606
cloning and sequence of a leishmania major homologue to the fibrillarin gene.		1994	7935615
interleukin-10 inhibits antimicrobial activity against leishmania major in murine macrophages.	the stimulation of macrophages is of importance to the defense against intracellularly replicating microorganisms such as leishmania. in this study the direct effect of recombinant interleukin-10 (il-10) on the leishmanicidal effector functions of murine peritoneal or bone marrow derived macrophages was investigated. il-10 almost completely inhibited the killing of intracellular leishmania at concentrations above 10 ng/ml. this inhibitory effect was independent of the stimulus used as the activa ...	1994	7939412
epidemiology and clinical manifestations of visceral and cutaneous leishmaniasis in baringo district, rift valley, kenya. a literature review.	visceral leishmaniasis (vl), caused by leishmania donovani, is endemic in baringo district, kenya. the disease has a focal distribution in the dry, hot areas below 1500 metres. infections may be characterized as follows: 1) asymptomatic, 2) subclinical and self-limiting (not medically identifiable), and 3) clinically manifest disease (that is medically identifiable). half of the reported vl patients are between 5 and 14 years of age and 66% of them are males. the reasons for the focal distributi ...	1994	7940999
infection of human monocytes by leishmania results in a defective oxidative burst.	the effect of infection by prototypes from the three major species of leishmania on the oxidative burst of human mononuclear phagocytes in culture was examined. the presence of intracellular parasites of the three species, l.major, l.donovani and l.mexicana decreased hydrogen peroxide (h2o2) and superoxide anion (o2-) production. this was particularly apparent when infected cells were compared to control monocytes following treatment with ifn-gamma. nitroblue tetrazolium (nbt) reduction by monoc ...	1994	7947230
solution structure and dynamics of a glycoinositol phospholipid (gipl-6) from leishmania major.	by use of a combination of 1h nuclear overhauser effect measurements, restrained molecular dynamics simulations, and 13c spin-lattice relaxation time measurements, the solution behavior of the glycan moiety of a complex glycoinositol phospholipid termed gipl-6, from the protozoan parasite leishmania major has been determined. the glycan moiety of gipl-6 has the following structure, which is characterized by the presence of an internal beta-galactofuranose residue: [formula: see text] the glycan ...	1994	7948729
leishmania major infection in mice primes for specific major histocompatibility complex class i-restricted cd8+ cytotoxic t cell responses.	this report shows that lymphoid tissues of mice which have resolved a primary infection with leisihmania major contain parasite-specific major histocompatibility complex (mhc) class i-restricted cytolytic cd8+ t cell precusors that can be expanded after specific restimulation in vitro with syngeneic antigen-presenting cells pulsed with a cyanogen bromide digest of l. major. in h-2b mice, two distinct populations of cd8+ t cells were identified which both lysed target cells pulsed with l. major-d ...	1994	7957573
leishmania major: association of the differentially expressed gene b protein and the surface lipophosphoglycan as revealed by membrane capping.	the lipophosphoglycan (lpg) of leishmania promastigotes forms a dense glycocalyx which effectively covers the entire surface of the cell, and which undergoes structural modifications during the differentiation of promastigotes to the infective or metacyclic stage. recently, the first protein marker for metacyclic promastigotes of leishmania major has been characterized. this protein, termed gene b protein, is located on the cell surface, yet it lacks any hydrophobic sequence for membrane attachm ...	1994	7957764
depletion of interleukin-4 in balb/c mice with established leishmania major infections increases the efficacy of antimony therapy and promotes th1-like responses.	whereas most inbred mouse strains mount a protective th1 helper t-cell response following infection with leishmania major, an ineffective th2 response develops in balb/c mice, leading to the development of disseminated, ultimately fatal disease. interleukin-4 (il-4) production is required for the initiation of the th2 response, though little is known about the requirements for the long-term maintenance of this response. in order to investigate the role of the expanding parasite population on the ...	1994	7960131
leishmania major-parasitized macrophages augment th2-type t cell activation.	we studied the ability of resident peritoneal m phi, parasitized in vitro with leishmania major, to present ag to three th2-type t cell clones that are specific for non-leishmanial ags. results indicated that l. major-infected m phi enhanced the proliferation and il-4 secretion of th2 t cells in response to stimulation with their cognate ag. augmentation of th2 t cell proliferation was seen in ag-driven responses but not in mitogenic con a stimulation. furthermore, live l. major promastigotes an ...	1994	7963516
th1/th2 cross regulation.	we present and analyze a model for the cross-regulation of the th1 and th2 helper cell subsets during an immune response by the regulatory cytokines interferon-gamma (ifn)-gamma) and interleukin-10 (il-10). ifn-gamma, secreted by th1 cells, can inhibit the proliferation of th2 cells. interleukin-10, secreted by th2 cells, inhibits cytokine production by th1 cells. based on these properties, the model shows that responses are expected to be dominated by either th1 cells or th2 cells but not both. ...	1994	7967633
evolution of codon usage and base contents in kinetoplastid protozoans.	in this study we analyze and compare the trends in codon usage in five representative species of kinetoplastid protozoans (crithidia fasciculata, leishmania donovani, l. major, trypanosoma cruzi and t. brucei), with the purpose of investigating the processes underlying these trends. a principal component analysis shows that the g+c content at the third codon position represents the main source of codon-usage variation, both within species (among genes) and among species. the non-trypanosoma spec ...	1994	7968492
detection of ubiquinone in parasitic and free-living protozoa, including species devoid of mitochondria.	ubiquinone (coenzyme q, coq) was analyzed and individual homologues quantified in 11 species of parasitic and free-living protozoa by a combination of thin-layer chromatography and high performance liquid chromatography. fast atom bombardment ionization-mass spectrometry was used for the first time to confirm the identity of the fractionated coq homologues and proved to be a fast, gentle and convenient method for ubiquinone identification. ubiquinone was detected in all organisms including those ...	1994	7969263
expression of a hydrophilic surface protein in infective stages of leishmania major.	a family of differentially expressed genes from leishmania major contains one sequence (gene b) that encodes a novel, hydrophilic protein found on the surface of infective parasite stages. the 177-residue, acidic gene b protein is characterised by an amino acid repetitive element, comprising 45% of the total molecule, that is related to the cell-wall binding domain of protein a from staphylococcus aureus. no identifiable signal peptide, membrane-spanning domain or consensus for glycosylphosphati ...	1994	7969267
ptr1: a reductase mediating salvage of oxidized pteridines and methotrexate resistance in the protozoan parasite leishmania major.	trypanosomatid protozoans are pterin auxotrophs, a finding noted decades ago which heralded the discovery of key metabolic roles played by pteridines in eukaryotes. we have now identified the enzyme mediating unconjugated pteridine salvage in the human parasite leishmania major, ptr1 (pteridine reductase 1, formerly hmtxr or ltdh). ptr1 is the gene in the amplified h region responsible for methotrexate (mtx) resistance, and belongs to a large family of oxidoreductases with diverse substrates and ...	1994	7972081
the xid defect determines an improved clinical course of murine leishmaniasis in susceptible mice.	the course of leishmania major infection in b cell-defective balb.xid mice was investigated. infected balb.xid mice showed a significantly slower lesion development compared with balb/c controls accompanied by a 10- to 30-fold lower parasite burden in lymphatic organs. the b cell immune response, as quantified by anti-leishmanial antibody production and b cell numbers in lymphatic organs, remained significantly lower in balb.xid mice as compared with balb/c control mice. in accordance with disea ...	1994	7981141
the isolation of leishmania major from phlebotomus (paraphlebotomus) caucasicus, in isfahan province, islamic republic of iran.	as part of a general survey of leishmaniasis and sandflies in the focus of zoonotic cutaneous leishmaniasis (zcl) at borkhar, a rural district north of the city of isfahan, central iran, phlebotomus (paraphlebotomus) caucasicus marzinowsky from gerbil and jird burrows were found naturally infected with leishmania major, zymodeme mon-26 (= lon-1). this is the first characterized isolate of l. major from a sandfly vector in iran.	1994	7992325
sporotrichoid cutaneous leishmaniasis due to leishmania major of different zymodemes in the sudan and saudi arabia: a comparative study.	sporotrichoid cutaneous leishmaniasis is due to dissemination of amastigotes via the lymphatics to the subcutaneous tissues. a comparison was made between the potential to disseminate by this route of 2 parasites of different zymodemes in sudan and saudi arabia. in sudan cutaneous leishmaniasis is caused by leishmania major zymodeme lon-1, and in saudi arabia by l. major lon-4. sporotrichoid leishmaniasis was significantly more common in sudan, occurring in 23% of patients compared with 10% in s ...	1994	7992336
th1-like human t-cell clones recognizing leishmania gp63 inhibit leishmania major in human macrophages.	the major surface protease of leishmania major, gp63, has been suggested as a vaccine candidate for cutaneous leishmaniasis. in this study gp63 was purified from l. major promastigotes. a panel of human t-cell clones recognizing this protein were generated from individuals who had previously had self-healing cutaneous leishmaniasis. the t-cell clones expressed cd4, and the alpha chain of the t-cell antigen receptor. gp63 reactive t-cell clones activated by antigen or by immobilized anti-cd3 anti ...	1994	7997852
glycoinositol-phospholipid profiles of four serotypically distinct old world leishmania strains.	glycoinositol-phospholipids (gipls) are the major glycolipid class and prominant surface antigens of leishmanial parasites. the gipls from four serologically distinct old world strains of leishmania were characterized to determine inter- and intra-specific differences in these glycolipids. these studies showed that: (1) the major gipls of leishmania topica (lrc-l36) and leishmania aethiopica (lrc-l495) belong to the alpha-mannose-terminating gipl series (im2, im3 and im4) that are structurally r ...	1994	7998997
dichotomy of the human t cell response to leishmania antigens. i. th1-like response to leishmania major promastigote antigens in individuals recovered from cutaneous leishmaniasis.	the t cell response to antigens from leishmania major promastigotes was investigated in peripheral blood mononuclear cells from sudanese individuals with a history of cutaneous leishmaniasis (cl), sudanese individuals with positive dth reaction in the leishmanin skin test but with no history of skin lesions, and in danes without known exposure to leishmania parasites. proliferation and production of interferon-gamma (ifn-gamma) and il-4 in antigen-stimulated cultures was measured. lymphocytes fr ...	1994	8004809
leishmania major hexbp deletion mutants generated by double targeted gene replacement.	the leishmania major single-stranded dna binding protein hexbp contains nine 'cchc' zinc finger motifs and binds to oligodeoxynucleotides derived from the antisense strand of the gp63 gene 5' flanking region in gel mobility shift assays and uv-crosslinking assays. in the present study a hexbp-deficient clone of l. major was generated by double targeted gene replacement. the two hexbp alleles were sequentially replaced with genes encoding resistance to the aminoglycoside antibiotics hygromycin b ...	1994	8008021
ricin-resistant mutants of leishmania major which express modified lipophosphoglycan remain infective for mice.	glycosylation variants of the virulent leishmania major clone v121 were generated by mutagenesis with n-methyl-n-nitroso-n-nitroguanidine and selected using the galactose-specific lectin ricinus communis ii (rca ii). three mutants, 4b9, 1d1 and 1c12, which failed to bind rca ii, were found to have an altered expression of lipophosphoglycan (lpg), a molecule implicated in the attachment to host macrophages and survival within the phagolysosome. there were differences in the antigenicity, molecula ...	1994	8008453
leishmania major surface protease gp63 interferes with the function of human monocytes and neutrophils in vitro.	in the present study the effect of leishmania major surface protease gp63 on the chemotaxis and oxidative burst response of human peripheral blood monocytes and neutrophils was investigated. it was shown that prior incubation of cells with gp63 inhibited chemotaxis of neutrophils but not monocytes towards the chemotactic peptide f-met-leu-phe. on the other hand, chemotaxis of both neutrophils and monocytes towards zymosan-activated serum containing c5a was inhibited by gp63. monocyte and neutrop ...	1994	8011303
[the use of leukinferon in treating zoonotic cutaneous leishmaniasis. 1. research on an experimental model in mice].	leukinferon, a drug made in this country, represents a complex of cytokines of the immune response first phase with the predominating activities of interleukin-1, tumor necrosis factor, macrophage- and leukocyte-inhibiting factors and alpha-interferon; its effects on the murine immune system and on peritoneal macrophagal culture are diverse. leukinferon activates phagocytosis and killing of l. major promastigotes with peritoneal macrophages. in vivo leukinferon in combination with monomycin had ...	1993	8028564
characterization of gdp-alpha-d-arabinopyranose, the precursor of d-arap in leishmania major lipophosphoglycan.	protozoan parasites of the genus leishmania synthesize a complex lipophosphoglycan (lpg), which is the major cell surface macromolecule. the lpg from leishmania major contains beta-d-arap-terminating side chains that are involved in regulating the attachment of the parasite to the midgut epithelium of its insect vector. an arabinose sugar nucleotide donor was identified in soluble extracts of l. major promastigotes. this sugar nucleotide was biosynthetically labeled with d-[2-3h]glc and with d-[ ...	1994	8034578
the use of a water-soluble formazan complex to quantitate the cell number and mitochondrial function of leishmania major promastigotes.	one of the methods to quantitate leishmania major promastigotes (lmp) has been to utilize the formation of a formazan dye, which in turn is produced via conversion of an artificial substrate, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (mtt). the method has one major drawback in that the formazan complex precipitates inside the parasites and has to be extracted by denaturants before measurements can be performed. by using a new synthetic substrate, 3-(4,5-dimethylthiazol-2-yl)-5 ...	1994	8036237
aminosidine ointments for the treatment of experimental cutaneous leishmaniasis.	a 15% aminosidine sulphate (as)/10% urea/white soft paraffin (wsp) ointment cured all leishmania major lesions on balb/c mice following topical application for 10 d. some relapses were observed 10 weeks after treatment. as alone in wsp ointment was also highly effective. the ointment containing urea was non-irritant to mice, whereas ointments containing quaternary ammonium compounds were irritant. the 15% as/10% urea/wsp ointment was not effective in the treatment of l. mexicana or l. panamensis ...	1994	8036682
comparison between leishmanins.		1994	8036694
pjc20 and pjc40--two high-copy-number vectors for t7 rna polymerase-dependent expression of recombinant genes in escherichia coli.	we report the construction of two plasmid vectors, pjc20 and pjc40, for the expression of recombinant genes in escherichia coli under the control of t7 rna polymerase. their small sizes of ca. 2.4 kb ease the subcloning of large inserts and the high copy numbers obtained result in satisfactory yields in all plasmid preparations. a multiple-cloning site offers sites for directional cloning and nested deletions. in addition, pjc40 encodes a cleavable amino-terminal histidine tail of 10 residues wh ...	1994	8054844
haemoglobin inhibits the development of infective promastigotes and chitinase secretion in leishmania major cultures.	haemoglobin or blood in the growth medium of leishmania major inhibited the formation of infective promastigotes and the secretion of chitinases. inoculation of mice with stationary-phase parasites from control medium caused infections in 20/29 mice, compared to 3/20 mice injected with parasites grown with 10% rabbit blood, or 1/30 mice that received parasites grown with rabbit haemoglobin. the concentration of peanut lectin (pna) required to agglutinate promastigotes was used as an index of the ...	1994	8058365
site-specific immunity to leishmania major in swr mice: the site of infection influences susceptibility and expression of the antileishmanial immune response.	inbred strains of mice usually develop either of two divergent patterns of infection in response to leishmania major. resistant mice, which develop self-limiting infections, respond immunologically with the activation of gamma interferon-secreting th1 helper t cells, while nonhealing infections in susceptible mice are characterized by the proliferation of interleukin-4-secreting th2 cells. development of these divergent responses is dependent primarily on the strain of mouse infected, although f ...	1994	8063382
proliferative response of human t cells to stimulation with leishmania infantum and l. major promastigotes in logarithmic and stationary growth phase.	t cells from healthy donors, non-exposed to leishmania, proliferative and produce lymphokines when cultured in the presence of killed leishmania promastigotes. we compared the stimulative activity of l. major and l. infantum promastigotes harvested in logarithmic and stationary growth phase on human t cells by performing a proliferation kinetics during the first 5 days of culture. stationary-phase promastigotes induced a good response at the 4th-5th day, whereas the effect of logarithmic-phase p ...	1994	8065279
stable dna transfection in a flagellate trypanosomatid by microparticle bombardment.		1994	8065951
[the therapy of cutaneous and mucocutaneous leishmaniasis].		1994	8076505
interaction between the innate and the acquired immune system following infection of different mouse strains with leishmania major.		1994	8080217
the developmental regulation and biosynthesis of gpi-related structures in leishmania parasites.	most macromolecules on the surface of leishmania parasites, including the major surface proteins and a complex lipophosphoglycan (lpg) are anchored to the plasma membrane via gpi glycolipids. free glycoinositol-phospholipids (gipls) which are not linked to protein or phosphoglycan are also abundant in the plasma membrane. from structural and metabolic labeling studies it is proposed that most leishmania species express three distinct pathways of gpi biosynthesis. some of these pathways (i.e. tho ...	1994	8081222
gpi phospholipase c from trypanosoma brucei causes a gpi-negative phenotype in leishmania major: i. implications for gpi-negative mammalian cells; ii. compartmentalization of two gpi biosynthetic pathways.	the major surface macromolecules of the protozoan parasite leishmania major, gp63 (a metalloprotease), and lipophosphoglycan (a polysaccharide) are glycosylphosphatidylinositol (gpi)-anchored. we expressed a cytoplasmic glycosylphosphatidylinositol phospholipase c (gpiplc) in l. major in order to examine the topography of the protein-gpi and polysaccharide-gpi pathways. in l. major cells expressing gpiplc cell-associated gp63 could not be detected in immunoblots. gp63 was secreted into the cultu ...	1994	8081227
does lipophosphoglycan enhance the t cell-stimulatory activity of lipophosphoglycan-associated proteins?	peripheral blood mononuclear cells (pbmc) from 13 american tegumentary leishmaniasis (atl) patients and two healthy controls were tested in in vitro proliferative response assays with crude lipophosphoglycan (lpg), purified lpg, lpg-associated proteins (lpgap) and synthetic lpgap from l. donovani. cells from another group of six atl patients were similarly tested with lpgap obtained from l. major. l. major lpgap was more stimulatory than l. donovani lpgap. crude lpg from l. donovani was signific ...	1994	8081281
[a fraction derived from non-protector extract of leishmania infantum protects balb/c mice against leishmania major infection].	we report the identification of a subfraction isolated by gel filtration liquid chromatography from a non-protective leishmania infantum extract, which protects balb/c mice against leishmania major infection, in conjunction with a bacterial adjuvant. protected mice exhibited cell-mediated immunity, as assessed by increased numbers of cd4+ and cd8+ spleen cells, and the production of ifn gamma, as compared to mice who received only the adjuvant before infection.	1993	8087613
suppression of antigen-specific t cell responses by leishmania major excreted factor: inhibition of activation signals linked to the t cell antigen receptor and interleukin 2 receptor.	an excreted factor (ef) derived from culture medium of leishmania major was found to suppress cona-induced polyclonal activation of mouse t cells. to further dissect the effect of ef on cell-mediated immune responses, we used in vivo primed antigen-specific murine lymph node cells. ef inhibited the proliferative response of keyhole limpet hemocyanin (klh) or ovalbumin (oa)-primed t cells upon in vitro challenge with the antigen. in addition, it suppressed the induction of interleukin 2 receptor ...	1994	8088978
evidence that the vectorial competence of phlebotomine sand flies for different species of leishmania is controlled by structural polymorphisms in the surface lipophosphoglycan.	phlebotomine vectors can in some instances transmit only certain species of leishmania. comparison of a large number of vector/parasite pairs revealed that species-specific differences in vectorial competence were in every case directly correlated with the ability of promastigotes to attach to the sand-fly midgut, the variable outcomes of which were controlled by structural polymorphisms in the surface lipophosphoglycan (lpg) of the parasite. the ability of phlebotomus papatasi to transmit only ...	1994	8090785
antileishmanial activity of licochalcone a in mice infected with leishmania major and in hamsters infected with leishmania donovani.	this study was designed to examine the antileishmanial activity of the oxygenated chalcone licochalcone a in mice and hamsters infected with leishmania parasites. intraperitoneal administration of licochalcone a at doses of 2.5 and 5 mg/kg of body weight per day completely prevented lesion development in balb/c mice infected with leishmania major. treatment of hamsters infected with l. donovani with intraperitoneal administration of licochalcone a at a dose of 20 mg/kg of body weight per day for ...	1994	8092835
persistence of virulent leishmania major in murine cutaneous leishmaniasis: a possible hazard for the host.	the persistence of leishmania major parasites in mice resistant to infection was investigated by the polymerase chain reaction and in vitro culture methods. parasite-specific dna was detected in the lymph nodes, spleens, bone marrow, and livers of c57bl/6 mice 1 year after their recovery from infection. live parasites were also recovered from these tissues (except liver tissues) and were used to establish in vitro isolates. pulsed-field gel electrophoresis, southern blotting, and western blot (i ...	1993	8093358
thioxanthenes inhibit multiplication of leishmania major and its attachment to human monocytes in vitro.		1993	8096111
t cell response in murine leishmania mexicana amazonensis infection: production of interferon-gamma by cd8+ cells.	the immune response to leishmania major has been the subject of many investigations. however, leishmania includes many species with different clinical manifestations. in this report, we studied the t cell response to l. mexicana amazonensis, a new world species, in a murine model. we found that, similar to l. major, an old world species, resistant c57bl/6 mice produced a high level of ifn-gamma and a low level of il-4. conversely, susceptible balb/c mice produced a much lower level of ifn-gamma ...	1993	8097471
recombinant interleukin 12 cures mice infected with leishmania major.	resistant c57bl/6 mice infected with leishmania major are self-healing, whereas susceptible balb/c mice fail to contain cutaneous infection and subsequently undergo fatal visceral dissemination. these disparate outcomes are mediated by dissimilar expansions of t helper type 1 (th1) and th2 cd4+ t lymphocyte subsets in vivo during cure and progression of disease. because interleukin 12 (il-12) has potent t cell growth and interferon gamma (ifn-gamma) stimulatory effects, we studied its effect on ...	1993	8097524
transfected leishmania expressing biologically active ifn-gamma.	infection of susceptible balb/c mice with leishmania major leads to progressive infection with the failure to expand and activate th1 cd4+ t cells that elaborate ifn-gamma, a critically implicated cytokine for control of disease. we used the recently described capacity to express foreign genes in trypanosomatids to introduce into leishmania the murine ifn-gamma gene on a drug-selectable plasmid under the constitutive control of intergenic tubulin sequences. several clones of l. major were establ ...	1993	8098724
resolution of cutaneous leishmaniasis: interleukin 12 initiates a protective t helper type 1 immune response.	resistance to leishmania major in mice is associated with the appearance of distinct t helper type 1 (th1) and th2 subsets. t cells from lymph nodes draining cutaneous lesions of resistant mice are primarily interferon gamma (ifn-gamma)-producing th1 cells. in contrast, t cells from susceptible mice are principally th2 cells that generate interleukin 4 (il-4). although existing evidence is supportive of a role for ifn-gamma in the generation of th1 cells, additional factors may be required for a ...	1993	8098733
natural killer cells are a source of interferon gamma that drives differentiation of cd4+ t cell subsets and induces early resistance to leishmania major in mice.	infection of mice with the protozoan leishmania major provides an excellent model to define the factors involved in t helper (th) subset development, since th1 cells confer protection in resistant strains of mice, whereas th2 cells are associated with the fatal outcome of susceptible mice. we previously found that interferon gamma (ifn-gamma) was required for th1 cell development after infection of mice with l. major. in this report, we evaluate the contribution of natural killer (nk) cells to i ...	1993	8101861
targeted activation of cd8 cells and infection of beta 2-microglobulin-deficient mice fail to confirm a primary protective role for cd8 cells in experimental leishmaniasis.	cd8+ t cells play an important role in the immunologic control of intracellular pathogens, particularly viruses. leishmania are obligate intracellular parasites of macrophages in the mammalian host, and previous studies using deletion of cd8+ cells by administration of mab to infected animals have suggested a protective role for these cells. two complementary approaches were used to define more carefully the role of cd8+ cells in leishmaniasis. in balb/c mice susceptible to leishmania major (l. ...	1993	8102158
leishmanin skin test survey in a focus of high endemicity of leishmania major in jordan.		1993	8103629
resistance of balb/c mice to leishmania major infection is associated with a decrease in the precursor frequency of antigen-specific cd4+ cells secreting interleukin-4.	balb/c mice are highly susceptible to infection with the protozoan parasite leishmania major and develop a chronic fatal disease. they can, however, be manipulated to resist disease and this has been shown to correlate with increased expression of ifn-gamma mrna and the absence of il-4 mrna in the draining lymph nodes and spleens of these animals. here we show that anti-il-4 or anti-cd4 treatment of balb/c mice resulted in a reduction in the size of the lesion and in the number of parasites in t ...	1993	8103672
licochalcone a, a novel antiparasitic agent with potent activity against human pathogenic protozoan species of leishmania.	licochalcone a, an oxygenated chalcone isolated from the roots of chinese licorice plant, inhibited the growth of both leishmania major and leishmania donovani promastigotes and amastigotes. the structure of the licochalcone a was established by mass and nuclear magnetic resonance spectroscopies and by synthesis, and its purity was verified by high-pressure liquid chromatography. the 50% inhibition of growth of logarithmic- and stationary-phase promastigotes of l. major, as measured by [3h]thymi ...	1993	8109916
cloning and sequencing of the leishmania major actin-encoding gene.	we report the cloning and characterization of the genomic sequence of the actin (act)-encoding gene (act) from leishmania major. restriction maps of two genomic clones, as well as genomic southern analysis strongly suggest that the act of l. major is a single-copy gene. a single 1.6-kb transcript is detected in northern blots. the deduced amino-acid sequence shows 68-89% identity with act sequences from other eukaryotes.	1994	8112581
relationships between cell surface protease and acid phosphatase activities of leishmania promastigote.	a correlation between the ratio of the cell surface protease activity to phosphatase activity and the complexity of the pattern of cell surface exposed polypeptides of leishmania promastigotes was demonstrated for various strains grown under similar conditions. the ratio of the cell surface protease activity to acid phosphatase activity was high for l. major and l.b. panamensis and it correlates with the expression of a single polypeptide of 63 kda on their cell surface. intermediate and lower r ...	1993	8114687
two more independent selectable markers for stable transfection of leishmania.	genetic transformation of leishmania has relied upon two exogenous selectable markers, neo and hyg, encoding resistance to g418 and hygromycin b respectively. there is a need for multiple independent selectable markers, since leishmania is diploid and experimental sexual crosses are not currently feasible. here we report on the development of two additional markers: pac, conferring resistance to the glycopeptide antibiotic puromycin, and phleo, conferring resistance to the dna-binding drug phleo ...	1993	8114824
identification, characterisation and genomic cloning of a o-linked n-acetylglucosamine-containing cytoplasmic leishmania glycoprotein.	antibodies against leishmania major wheat germ agglutinin-binding glycoproteins were used to select from a genomic lambda gt11 expression library a clone coding for a l. major glycoprotein. the partial dna sequence indicated the presence of a mosaic of repetitive sequences. southern blot hybridisation on genomic dna using the cloned gene as a probe at high stringency suggested a single gene, which was localised to chromosome band 18. northern blot analysis of l. major mrna detected a major trans ...	1993	8114827
cloning and characterization of a golgi-associated gtp-binding protein homologue from leishmania major.	this paper describes the cloning of a golgi-associated gtp-binding protein homologue from leishmania major. the gene was isolated using degenerate oligonucleotides to conserved sequences amongst the small gtp-binding proteins in a polymerase chain reaction on genomic dna of the l. major cloned line v121. the reading frame of one clone showed high similarity to the rab/ypt subfamily of small gtp-binding proteins. a full length copy of the gene was isolated from a lambda gt10 v121 genomic library ...	1993	8114828
leishmania major: organization and conservation of genes encoding repetitive peptides and subcellular localization of the corresponding proteins.	proteins containing tandemly repeating peptide sequences are characteristic of several parasite antigens. previously it was reported that leishmania major contain two genes, lm20 and lm39, consisting of two unrelated repeat sequences of 42 and 30 base pairs (bp), respectively. in present study l. major was shown to contain two genes that contained the lm20 42-bp repeat sequence and that the 42-bp repeat sequence was highly conserved among both old and new world leishmania species. the two l. maj ...	1994	8119372
production of nitric oxide and superoxide by activated macrophages and killing of leishmania major.	murine macrophages can be activated to produce nitric oxide (no) and superoxide and these two radicals can react to form peroxynitrite, a powerful oxidant which may be involved in parasite killing. we now show that murine macrophages activated with zymosan and interferon-gamma (zym/ifn-gamma) produced both superoxide (peaking 1-2 h after stimulation, then rapidly declining) and no (barely detectable at 6 h, peaking by 24 h). macrophages activated with zym alone produced only superoxide, while st ...	1994	8125136
cytokines in leishmaniasis: a complex network of stimulatory and inhibitory interactions.	the work of immunologists, cell biologists and parasitologists in the field of leishmaniasis has not only provided important insights into the immunopathogenesis of this disease, but also yielded fundamental contributions to our understanding of basic immunological phenomena and of host-parasite interactions. the ability of recombinant interferon-gamma to induce the microbicidal activity of phagocytes and the opposite effect of inhibitory cytokines was first demonstrated with leishmania-infected ...	1993	8125517
differential regulation of il-9-expression after infection with leishmania major in susceptible and resistant mice.	il-9 is a pleiotropic lymphokine, one of its activities being the growth stimulation of certain cd4+ t lymphocytes. in murine cutaneous leishmaniasis, depending on the genetic background of the host mouse strain, vigorous proliferation of either mainly th1 in resistant c57bl/6 mice or th2-type cd4+ t cells in susceptible balb/c mice occurs after infection with leishmania major (l. major). since little is known about the involvement of il-9, the possible role of this cytokine with regard to its i ...	1993	8125519
[the isoenzyme identification of leishmania isolates taken from greater gerbils, sandflies and human patients in foci of zoonotic cutaneous leishmaniasis in turkmenistan].	in 1991-1992, 230 isolates were obtained in the tedzhen oasis and its adjacent desert areas: 172 isolates from great gerbils, 39 from p. papatasi, and 19 from human cutaneous leishmaniasis patients. all the isolates were identified by the isoenzyme polyacrylamide gel electrophoresis by 8 enzymes. the characteristics of leishmania circulation in the hyperendemic foci of turkmenistan were similar to those previously studied in the mesoendemic areas of uzbekistan and kazakhstan. l. turanica which i ...	1993	8127269
[the extra-burrow activity of the vectors of the causative agents of zoonotic cutaneous leishmaniasis].		1993	8127270
tumor necrosis factor alpha (tnf-alpha) and tnf-beta and their receptors in experimental cutaneous leishmaniasis.	experimental infection of balb/c mice with leishmania major leads to lesions which progress without healing and visceralization, reproducing the most severe forms of human leishmaniasis, while resistant mice like cba spontaneously resolve lesions and develop protective immunity. given the conflicting data pertaining to the role of tumor necrosis factor alpha (tnf) in leishmania infection, we analyzed the expression of tnf, tumor necrosis factor beta (lymphotoxin), and tnf receptor type i (tnf-ri ...	1994	8132347
a glycosylphosphatidylinositol (gpi)-negative phenotype produced in leishmania major by gpi phospholipase c from trypanosoma brucei: topography of two gpi pathways.	the major surface macromolecules of the protozoan parasite leishmania major, gp63 (a metalloprotease), and lipophosphoglycan (a polysaccharide), are glycosylphosphatidylinositol (gpi) anchored. we expressed a cytoplasmic glycosylphosphatidylinositol phospholipase c (gpi-plc) in l. major in order to examine the topography of the protein-gpi and polysaccharide-gpi pathways. in l. major cells expressing gpi-plc, cell-associated gp63 could not be detected in immunoblots. pulse-chase analysis reveale ...	1994	8132715
serial study of the immune response of an individual with exacerbated simple cutaneous leishmaniasis.	the immunological responses of a patient with exacerbated cutaneous leishmaniasis, measured during the course of the disease, are described. except for skin lesions the patient was healthy and showed no signs of immunosuppression. three immunological parameters were measured: specific lymphocyte proliferation (lpa), monocyte effector activity (mea), and antibody levels. lpa was positive early in the course of the disease, became negative as the lesions enlarged, and was positive again as the les ...	1994	8138392
sequence and genomic organization of the hsp70 genes of leishmania amazonensis.	the sequence and genomic organization of hsp70 genes in leishmania amazonensis were examined. maps of overlapping cosmid clones revealed that seven l. amazonensis hsp70 genes are organized into a 24-kb locus containing 3.5-kb tandem repeats. cosmids covering a different chromosomal region indicated that an eighth hsp70 sequence is located at a distant site. southern blot data suggested the existence of additional hsp70 genes or pseudogenes. one complete 3.5-kb genomic repeat unit, including codi ...	1993	8139614
characterisation of two soluble metalloexopeptidases in the protozoan parasite leishmania major.	two soluble exopeptidases were identified in promastigotes of leishmania major, using an iodinated model tetrapeptide (liay) as substrate. similar activities were also detected in l. major amastigotes and in different species of leishmania promastigotes. a carboxy- and an aminopeptidase activity were resolved and isolated by anion exchange and gel permeation chromatographies. a single polypeptide of 62 kda co-purified with the aminopeptidase activity. optimum ph was neutral for the carboxypeptid ...	1993	8139615
mutational analysis of a signal sequence required for protein secretion in leishmania major.	in eukaryotes, amino-terminal extensions, signal sequences, mediate the translocation of lysosomal, membrane and secreted proteins into the lumen of the endoplasmic reticulum (er). structure/function studies indicate that eukaryotic signal sequences are composed of 3 distinct domains, a positively charged amino-terminal domain, a central hydrophobic domain, and a polar carboxy-terminal domain. in an attempt to better understand protein trafficking in leishmania we have constructed strains of lei ...	1993	8139617
identification of a histone h1-like gene expressed in leishmania major.		1993	8139626
[cellular immunity and vaccination against cutaneous leishmaniasis. recent progress and prospects].	review of leishmaniasis immunopathogenesis, the models in the laboratory animals, and the last advances in the experimental vaccine administration. in recent years, there have been important progresses that have contributed substantially to classify the role of the interleukins and other chemical mediators in the immunologic response. all these advances open the door to the production of better and more immunogenic vaccines, that in a near future will be employed advantageous in the human beings ...	1993	8143026
isolation and characterization of a mutant dihydrofolate reductase-thymidylate synthase from methotrexate-resistant leishmania cells.	the mtx-resistant leishmania major promastigote cell line d7br1000 displays extrachromosomal amplified r-region dna, which contains the gene for dihydrofolate reductase-thymidylate synthase (dhfr-ts) (garvey, e. p., and santi, d. v. (1986) science 233, 535-540). now we report that these methotrexate (mtx)-resistant cells also possessed a structurally altered dhfr-ts. we have performed the cloning, expression, and characterization of the altered dhfr-ts gene. the dna sequence of the altered dhfr- ...	1994	8144647
meriones libycus (rodentia: gerbillidae), a possible reservoir host of zoonotic cutaneous leishmaniasis in riyadh province, saudi arabia.		1994	8153994
phlebotomus papatasi (scopoli), vector of zoonotic cutaneous leishmaniasis in riyadh province, saudi arabia.		1994	8153996
mast cells augment lesion size and persistence during experimental leishmania major infection in the mouse.	mast cells are a source of a variety of cytokines that may influence the host response to leishmania major. to investigate the role of mast cells during l. major infection, we performed a morphometric analysis of mast cells at cutaneous sites in resistant c57bl/6 mice and susceptible balb/c mice injected with l. major. extensive dermal mast cell degranulation was found at sites of l. major infection in both strains of mice. we also examined the course of l. major infection in genetically mast ce ...	1994	8157970
an investigation into the significance of the n-linked oligosaccharides of leishmania gp63.	leishmania major promastigotes, when grown in the presence of tunicamycin (tm), produced a plasma membrane-bound, proteolytically active gp63 with a lower molecular weight than the native glycoprotein. however, this lower molecular weight form of gp63 continued to be recognized by concanavalin a (con a), suggesting that inhibition of n-linked glycosylation was not complete. metabolic labeling of gp63, using [35s]methionine, demonstrated that in the range of 5-10 micrograms ml-1 tm, only the lowe ...	1994	8183321
expansion of gamma interferon-producing cd8+ t cells following secondary infection of mice immune to leishmania major.	reinfection of immune mice with leishmania major elicits a secondary gamma interferon (ifn-gamma) response to which specific cd8+ t cells are essential. we have shown previously that specific cd8+ t cells from reinfected immune mice release substantially higher levels of ifn-gamma, a cytokine essential for the efficient activation of parasitized macrophages to kill intracellular l. major. by using an elispot assay, which allows the detection of ifn-gamma production by individual cells, it is sho ...	1994	8188380
the macrophage-activating tetrapeptide tuftsin induces nitric oxide synthesis and stimulates murine macrophages to kill leishmania parasites in vitro.	the macrophage-activating tetrapeptide tuftsin was able to activate, in a dose-dependent manner, murine macrophages to express nitric oxide (no) synthase and to produce no. tuftsin required lipopolysaccharides for the optimal induction of no production and synergized with gamma interferon in the induction of no synthesis. tuftsin-dependent no production was sensitive to inhibition by dexamethasone and the no synthase specific inhibitor lgn-monomethylarginine (l-nmma). murine peritoneal macrophag ...	1994	8188392
trypanosoma cruzi affects nitric oxide production by murine peritoneal macrophages.	macrophages from mice that are infected with various intracellular pathogens including leishmania major, trypanosoma cruzi, and salmonella typhimurium are stimulated to produce large quantities of nitric oxide (no). both viable and heat-treated l. major amastigotes have been shown to be effective co-signals for no production in vitro. no produced by macrophages has anti-microbial and immunosuppressive functions in an immune response. we have shown previously that no plays a complicated role in t ...	1994	8195945
extracellular phosphorylation in leishmania major and leishmania mexicana during heat shock transformation.	the extracellular phosphorylation of exogenous substrates have been studied in two leishmania isolates, l. mexicana and l. major, that differ in their capacity to transform from promastigotes to amastigote-like cells when submitted to heat shock condition. when submitted to heat shock both parasites showed an increase in their extracellular phosphorylation activity. l. major promastigotes that do not transform to amastigote-like cells at 37 degrees c, do not phosphorylate exogenous substrate whe ...	1994	8203291
use of recombinant dna probes for species identification of old world leishmania isolates.	recombinant dna probes from a genomic leishmania major library were screened for their potential to distinguish among old world leishmania taxa by southern blot analysis. a probe, pdk10, was selected and tested on a panel of 58 old world leishmania strains that had already been typed isoenzymatically; these strains belong to the different species described so far and had been isolated from various hosts and vectors in 14 countries. in the present study, 45 zymodemes were represented. using the p ...	1994	8203714
anti-galactosyl antibodies that react with unmodified agarose: a potential source of artifacts in immunoaffinity chromatography.	rabbits were immunized with glycolipid and membrane glycoprotein extracts of the promastigotes of leishmania major partially purified by two-phase extraction with triton x-114. the resulting antibodies were affinity purified on agarose immunoadsorbents to which a recombinant dna-produced l. major polypeptide had been coupled. in addition to the expected reaction with the polypeptide, it was found that the affinity-purified antibodies reacted strongly with lipophosphoglycan of l. major amastigote ...	1994	8203745
on the introduction of genetically modified leishmania outside the laboratory.		1994	8206143
binding of c-reactive protein to leishmania.		1994	8206251
the role of anions in ph regulation of leishmania major promastigotes.	the ph regulation of leishmania major promastigotes was studied as a function of the ionic composition of the medium and in response to acid and alkali load. intracellular ph (phi) was monitored by on-line ratio fluorescence using the fluorescence-dependent ph indicator 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein (bcecf). in cl(-)-based medium (ph 7.4, 30 degrees c), the steady state phi was maintained at 6.75 +/- 0.01. only a minor (< or = 0.07 +/- 0.02 unit) decrease in steady state phi wa ...	1994	8206930
interleukin-4 and interleukin-10 synergize to inhibit cell-mediated immunity in vivo.	the lack of cell-mediated (th1-like) immunity that is often associated with strong humoral immune responses is thought to be due in part to the inhibition of th1 effector function by the th2-derived cytokine interleukin-10 (il-10). this hypothesis, however, is based entirely on results from in vitro studies, wherein il-10 has been shown to inhibit th1 cytokine synthesis. in this study we have compared the regulatory effects of both il-4 and il-10 on the development of a more complex th1 effector ...	1993	8223881
a heparin-binding activity on leishmania amastigotes which mediates adhesion to cellular proteoglycans.	the intracellular amastigote form of leishmania is responsible for the cell-to-cell spread of leishmania infection in the mammalian host. in this report, we identify a high-affinity, heparin-binding activity on the surface of the amastigote form of leishmania. amastigotes of leishmania amazonensis bound approximately 120,000 molecules of heparin per cell, with a kd of 8.8 x 10(-8) m. this heparin-binding activity mediates the adhesion of amastigotes to mammalian cells via heparan sulfate proteog ...	1993	8227137
salivary gland material from the sand fly lutzomyia longipalpis has an inhibitory effect on macrophage function in vitro.	previous work from our laboratory demonstrated that the infectivity of the protozoan parasite leishmania major was enhanced in mice if the infecting inoculum contained salivary gland lysates from the sand fly vector lutzomyia longipalpis. the present study was designed to address the hypothesis that sand fly salivary gland material may function by inhibiting the host immune response. results indicated that sand fly saliva inhibited the ability of macrophages to present leishmanial antigens to pa ...	1993	8233563
characterization of glycoinositol phospholipids in the amastigote stage of the protozoan parasite leishmania major.	the major macromolecules on the surface of the parasitic protozoan leishmania major appear to be down-regulated during transformation of the parasite from an insect-dwelling promastigote stage to an intracellular amastigote stage that invades mammalian macrophages. in contrast, the major parasite glycolipids, the glycoinositol phospholipids (gipls), are shown here to be expressed at near-constant levels in both developmental stages. the structures of the gipls from tissue-derived amastigotes hav ...	1993	8240257