| [new data on the biology of gametocytes of plasmodium yoelii yoelli gathered from morphological characteristics indicating their age]. | a morphological study has been made of the gametocytes of p. yoelii (a parasite of rodents belonging to the "vivax" group). the authors distinguish 4 types chronologically ordered. moreover, morphology enables one to predict their infectivity. the morphological analysis represents a tool leading to new data on the biology of gametocytes: loss of infectivity as soon as the parasitaemia becomes high; infectivity restricted to the young stages; concentration of young stages in the blood ingested by ... | 1979 | 108020 |
| development and suppression of a population of late-adhering macrophages in mouse malaria. | changes in phagocytic and adherent cell numbers were compared during the course of infections of mice with plasmodium yoelii (py) and p. berghei (pb) and in vaccinated mice challenged with homologous parasites. nucleated cells in the spleen increased in number in py-infected mice and were maximal at the time of recovery. the number of phagocytic cells increased in parallel, as did the number of blood leucocytes. rates of increase were accelerated in vaccinated mice. changes in pb-infected mice r ... | 1979 | 233150 |
| antibody response in vitro of spleen cells from plasmodium yoelii-infected mice. | the primary antibody response to sheep erythrocytes and dinitrophenylated ficoll of spleen cells from mice infected with plasmodium yoelii was studied in vitro. the response to sheep erythrocytes was enhanced between 2 and 4 days after infection and depressed at later intervals. cell fractionation experiments carried out at the time of immunosuppression indicated a defect of macrophage function. at the same time the response to dinitrophenylated ficoll was normal. | 1977 | 324908 |
| plasmodium yoelii and plasmodium vinckei: the effects of nonspecific immunostimulation on murine malaria. | | 1977 | 330190 |
| influence of rodent malaria on the course of leishmania enriettii infection of hamsters. | plasmodium yoelii infection was established in hamsters, and the effect of this type of malaria on concurrent leishmania enriettii infection was examined. it was found that the course of the l. enriettii infection was affected by p. yoelii and that this effect depended on the relative timing of the two infections. a chronic malarial infection with plasmodium berghei was also established in hamsters, and this was found to affect the course of a concurrent l. enriettii infection in a similar manne ... | 1976 | 786886 |
| inhibition of the immune response to whooping cough and tetanus vaccines by malaria infection, and the effect of pertussis adjuvant. | plasmodium yoelii infection of mice depressed their capacity to build up humoral immune response to diphteria vaccine and protective immunity against tetanus toxin. this immunodepression was overcome by freund's complete adjuvant or killed pertussis bacilli (whooping cough vaccine). these results suggest that vaccines should be given in association in malaria endemic area. | 1977 | 869103 |
| splenomegaly, enhanced phagocytosis, and anemia are thymus-dependent responses to malaria. | immunologically competent mice and mice with defined immunological deficiencies were infected with plasmodium yoelii. splenomegaly, enhanced phagocytosis, and anemia were most marked in infected mice having intact thymic tissue. whereas the spleens of infected nude mice increased minimally in size, the relative blood hemoglobin levels and the rates of carbon clearance in these mice were similar to those of noninfected, immunologically intact mice. thymus-reconstituted nude mice and b-cell-defici ... | 1978 | 669820 |
| immunosuppression in murine malaria. ii. the primary response to bovine serum albumin. | the primary antibody response to alumadsorbed bovine serum albumin was depressed in cba mice infected with plasmodium yoelii yoelii. responses initiated within approximately 3 weeks of this malaria infection were reduced in quantity, but not in avidity. responses initated later were normal. a depressed primary response was also seen in infected compared to control splenectomized mice; this was accompanied by impaired priming for a secondary response. | 1977 | 608688 |
| [study of gametocytes from the plasmodium "vivax" group: morphology, development in anopheles and infectivity of plasmodium yoelii microgametocytes]. | the study of the gametocytes of plasmodium yoelii enabled the differentiation of 4 morphological types: o, i, ii and iii (in a chronological order) and amongst each of these types the differentiation of healthy and altered gametocytes. these morphological data represent a tool for investigations on the biology of the gametocytes of the "vivax" group. preliminary experiments bring informations on the evolution of gametocytes and the mechanisms of their infectivity. 1--in experimentaly infected wh ... | 1979 | 539716 |
| host defenses in murine malaria: evaluation of the mechanisms of immunity to plasmodium yoelii infection. | the immune response of random-bred mice to infection with a relatively avirulent strain of plasmodium yoelii was measured in terms of parasitemia, splenomegaly, immediate and delayed hypersensitivity to a p. yoelii antigen preparation, resistance to challenge with a virulent variant of p. yoelii, and nonspecific resistance to l. monocytogenes. avirulent p. yoelii produced a self limiting infection which resolved in 21 days. peak parasitemia and splenomegaly were observed at 14 days, and infected ... | 1979 | 422246 |
| immunosuppression in murine malaria. iv. the secondary response to bovine serum albumin. | the anamnestic antibody response of cba mice to bovine serum albumin was characterized by a rapid production of high-avidity antibody. after 3 weeks both the total amount of antibody and its avidity declined but still remained above those seen in the primary response for at least 6 weeks. the effects of acute plasmodium berghei and plasmodium yoelii yoelii infections upon the induction and the expression of this anamnestic response were studied. mice infected with these malaria parasites respond ... | 1979 | 399334 |
| biochemistry of intraerythrocytic parasites. ii. comparative studies in carbohydrate metabolism. | comparative studies were carried out on the glucose catabolism of mouse erythrocytes infected with plasmodium berghei, plasmodium yoelii, babesia rodhaini, babesia microti and anthemosoma garnhami, as well as on uninfected erythrocytes and reticulocytes. the results showed that there was little qualitative difference between the glucose utilization and lactate production of the parasites although quantitative differences between malaria parasites and piroplasms were observed. the rate of glucose ... | 1979 | 386968 |
| biochemistry of intraerythrocytic parasites. i. identification of enzymes of parasite origin by starch-gel electrophoresis. | enzymes of parasite origin were identified by starch-gel electrophoresis. the species of parasite studied were plasmodium berghei, plasmodium yoelii nigeriensis, babesia rodhaini and anthemosoma garnhami. lactate dehydrogenase, glucose phosphate isomerase and (nadp) glutamate dehydrogenase were detected in all species; phosphogluconate dehydrogenase was detected in both plasmodium species but malate dehydrogenase only in p. y. nigeriensis. glucose-6-phosphate dehydrogenase, alanine aminotransfer ... | 1979 | 386967 |
| [effect of sodium artesunate on plasmodium yoelii analysed by flow cytometry]. | the effect of sodium artesunate on plasmodium yoelii-infected mouse erythrocytes was analysed by flow cytometry. the results showed that malarial dna content in experimental group was obviously decreased 2-5 hours after the drug was administered, fluorescence distribution of malarial dna almost disappeared within 24 hours after the administration. thus we deem that sodium artesunate can inhibit the dna synthesis in p. yoelii. | 1992 | 1307277 |
| [malaria plasmodia in the mouse. parasitization of mature and immature erythrocytes by plasmodium berghei, plasmodium yoelii and plasmodium chabaudi (author's transl)]. | plasmodium berghei parasites (strain k173) in mice with developing immunity changed to a variant type with increased resistance against antibodies and enhanced invasion of mature erythrocytes; on passages in normal mice this variant type retransformed to the normal type (kretschmar 1964). on detailed study, parasites of the variant type showed a markedly decreased predilection for polychromatophilic erythrocytes, leading to slowed multiplication during prepatency, increased invasion of mature er ... | 1979 | 384629 |
| protection of mice against plasmodium and babesia infections: attempts to raise host-protective sera. | in an attempt to generate large numbers of mice resistant to plasmodium berghei and babesia rodhaini to be used as donors of antibody-secreting cells for hybridoma production, various methods of inducing resistance to repeated challenge with infected blood cells have been explored. although results of independent experiments varied markedly, prior injection of cba/m mice with bcg, and prior infection of balb/c mice with plasmodium yoelii, were found to be manipulations capable of inducing resist ... | 1978 | 375903 |
| chronic malarial infection of mice: a comparison of single and multiple infections with plasmodium berghei following p. yoelii. | chronic malarial infection was induced in two groups of balb/c mice by injection of plasmodium yoelii followed by either one or repeated injections of p. berghei. both groups showed a continuing but fluctuating splenomegaly, and a considerably increased reticulocyte count which also varied regularly, over a period of six months. during this time many mice had a very low grade parasitaemia demonstrable by subinoculation of blood into uninfected recipients. mice infected with p. yoelii alone did n ... | 1978 | 366816 |
| lethal plasmodium yoelii malaria: the role of macrophages in normal and immunized mice. | mice were injected with silica or corynebacterium parvum, which, respectively, inhibit and stimulate macrophages in vivo, in an attempt to study the role of macrophages in lethal plasmodium yoelii infection and in mice protected by immunization. in the normal infection, macrophages were able to control parasitaemia for up to 1 week, whereas in immunized mice they appeared to inhibit the sterilizing immune response. a model is proposed in which this dual role of activated macrophages may account ... | 1979 | 317443 |
| influence of the sex-linked defect in cba/n mice on autoimmune responses to isologous erythrocytes. ability to overcome the defect with age. | normal mice spontaneously develop plaque-forming cells (pfc) specific for antigens on modified self erythrocytes (bromelain-treated mouse erythrocytes [brmrbc] antigens). our study demonstrates that the sex-linked defect that results in the inability of cba/n mice to respond to several t-independent antigens (ti-2 antigens) also regulates the autoantibody response to brmrbc antigens. thus, in cba/n homozygous mice and male f1 offspring of cba/n-mothered crosses, e.g., (cba/n x nzb)f1 males, such ... | 1979 | 315995 |
| t-cell immunity to malaria in the b-cell deficient mouse. | some b-cell deficient mice drug-rescued with clindamycin hcl from otherwise lethal infections with plasmodium yoelii resisted subsequent challenge with the same parasite despite the fact that they lacked detectable antibody to plasmodia. parasitemias remained patent but at low levels (less than or equal to 5%) in these mice for prolonged periods of time, suggesting that some t-cell function independent of antibody formation can in part mediate immunity to malaria. | 1979 | 312025 |
| ia antigens in serum during different murine infections. | there exists in the mouse a family of i-region-controlled (ia) antigens which carry carbohydrate-defined determinants. these antigens appear in serum as glycolipids and seem to be actively secreted by antigen-activated t-cells. this paper describes the ability of selected viral, bacterial, and protozoal infections of mice to markedly alter the serum levels of these ia antigens. all the infectious agents examined induced substantial augmentation or suppression of serum ia concentrations or both. ... | 1979 | 94905 |
| immunosuppression in murine malaria. i. response to type iii pneumococcal polysaccharide. | acute plasmodium yoelii yoelii and chronic plasmodium berghei malaria infections of cba mice were accompanied by a reduced capacity to give an antibody response to type iii pneumococcal polysaccharide (siii). the depression of response initiated by acute malaria persisted for several weeks after recovery from clinical infection. during chronic infection, and at the peak of acute parasitaemia, virtually no response to siii was detected. a substance which crossreacted serologically with siii was f ... | 1977 | 67996 |
| gametogenesis and fertilization in plasmodium yoelii nigeriensis: a transmission electron microscope study. | | 1976 | 4810 |
| the action of metabolic inhibitors on microgametogenesis in plasmodium yoelii nigeriensis. | mature gametocytes of plasmodium yoelii nigeriensis were incubated in vitro with a variety of antibiotics whose activities were directed against dna, rna, protein and microtubule assembly. following incubation for periods between 5 and 90 min, exflagellation was induced and the degree of inhibition produced by each drug was assayed microscopically. the results obtained show that de novo synthesis of axonemes and proteins is essential to the events of microgametogenesis. the inhibitory effect of ... | 1977 | 919692 |
| cytofluorograf detection of plasmodium yoelii, trypanosoma gambiense, and trypanosoma equiperdum by laser excited fluorescence of stained rodent blood. | samples of rat blood infected with plasmodium yoelii (3% parasitized erythrocytes), trypanosoma gambiense, or trypanosoma equiperdum (greater than 50 trypanosomes per microscope field at 400 x) were fixed with 0.5% glutaraldehyde in phosphate buffered saline, then stained with acridine orange (ao) at 10(-4), 10(-5), or 10(-6) m for 0 to 15 min at 5 c or 25 c and/or ethidium bromide (eb) at 0.05 mg/ml for 20 min at 25 c. stained cells were analyzed with a laser cytofluorograf (bio/physics systems ... | 1977 | 886402 |
| plasmodium yoelii: an inbred model for protective immunization against malaria in balb/c mice. | | 1977 | 849768 |
| trials to infect anopheles stephensi with plasmodium yoelii nigeriensis by the membrane feeding technique. | the aim of this study was to find optimal conditions for the membrane feeding technique to obtain maximum infection rates of mosquitoes with plasmodium yoelii nigeriensis. the results show that the malaria parasite plasmodium yoelii nigeriensis is most infective to anopheles stephensi mosquitoes on day 3 of the infection in the mice, 1 day before the peak of parasitaemia. the mortality rate of the mosquitoes fed on mice on day 3 after infection was the highest as compared to mosquitoes fed on ot ... | 1992 | 1456466 |
| [blood relapses and modifications of the pre-erythrocytic shizonts of plasmodium yoelii using ethionine]. | injections of dl-ethionine during the preerythrocytic period of plasmodium yoeli in thammomys were followed by: 1. a delayed prepatent period; 2. a relapsing parasitaemia with alternatively positive and negative blood at subinoculation of clean mice; 3. a peculiar morphology of the exoerythrocytic schizonts which remain small with a scanty cytoplasm and very few large nuclei. although the authors consider the origin of the relapses to be the rupture of delayed hepatic schizonts under the influen ... | 1975 | 807419 |
| schizont-infected cell enrichment in rodent malaria. | mouse erythrocytes parasitized with plasmodium berghei or plasmodium yoelii were separated by ultracentrifugation using preformed isodensity gradients of the discontinuous type. three fractions were obtained following centrifugation, the upper of which contained greater than 90% of all schizont-infected cells added to the gradient. the gradient material, stractan ii, is an arabinogalactan polysaccharide and appears to yield results similar to those available using gradients of bovine serum album ... | 1976 | 789847 |
| exacerbation of murine malaria by concurrent infection with lactic dehydrogenase-elevating virus. | the simultaneous infection of mice with lactic dehydrogenase-elevating virus (ldv) and plasmodium yoelii resulted in an exacerbated attack of malaria. peak parasitaemia was higher and the patent infection more prolonged in doubly infected mice. the results indicate that contamination with ldv must be considered when a change in parasite virulence is observed, particularly when the parasite is maintained by blood passage in mice. | 1978 | 719954 |
| the chemotherapy of rodent malaria, xxiii causal prophylaxis, part ii: practical experience with plasmodium yoelii nigeriensis in drug screening. | data are presented on the causal prophylactic action of about 100 compounds of various types against plasmodium yoelii nigeriensis n67 in mice. examples are given to show how action against pre-erythrocytic schizonts may be differentiated from action on emerging erythrocytic stages. in a series of 35 8-aminoquinolines, all but 10 showed definite causal prophylactic activity at tolerated doses. the data permit the compounds to be ranked in order of activity, and many are shown to be more active i ... | 1975 | 1098590 |
| new observations on the malaria parasites of rodents of the central african republic - plasmodium vinckei petteri subsp. nov. and plasmodium chabaudi landau, 1965. | the morphology and enzyme forms of malaria parasites isolated from 50 wild caught specimens of thamnomys rutilans from the central african republic have been studied and three distinct species of plasmodium identified. one species has been confirmed as plasmodium yoelii yoelii. morphological features of both the remaining species correspond to those given by landau (1965) in her original description of plasmodium chabaudi. for one of these species the name p. chabaudi has been retained; the othe ... | 1975 | 1155987 |
| defective resistance to plasmodium yoelii in cba/n mice. | the role of b lymphocytes in resistance to malaria was studied in defective and normal f1 mice derived from cba/n mice, a strain with an x-linked b cell defect. when infected with normally nonlethal plasmodium yoelii, immune defective f1 male mice had higher parasitemias and more prolonged infections than normal f1 mice, as well as a 50% mortality rate. before infection the plasma levels of igm and igg were lower in defective f1 males than normal f1 mice. the polyclonal igm and igg responses of ... | 1979 | 448143 |
| the effects of nosema algerae on the development of plasmodium yoelii nigeriensis in anopheles stephensi. | experimental simultaneous infections of anopheles stephensi (diptera: culicidae) with nosema algerae (microsporida: nosematidae) and plasmodium yoelii nigeriensis under standardized laboratory conditions showed partial suppression of the malaria parasite. at 9 days after an infective bloodmeal, the oocysts in the midgut were counted; 12.1%-66.6% of the double-infected mosquitoes exhibited no oocysts, whereas only 4.5%-12% of the control group showed no oocysts. the mean reduction in oocyst numbe ... | 1992 | 1584748 |
| a genetic investigation of virulence in a rodent malaria parasite. | the genetic basis of virulence in a line (ym) of plasmodium yoelii yoelii was investigated in a cross with a mild line (a/c). the blood forms of the virulent line developed extensively in mature erythrocytes of mice, causing death of the host within 7 days; infections with the mild line were normally restricted to reticulocytes, infected animals recovering after three weeks. lines ym and a/c differed additionally in enzyme and drug-sensitivity markers. studies on infections established from each ... | 1976 | 1264490 |
| kinetics of antigen specific and non-specific polyclonal b-cell responses during lethal plasmodium yoelii malaria. | in order to study the kinetics and composition of the polyclonal b-cell activation associated to malaria infection, antigen-specific and non-specific b-cell responses were evaluated in the spleens of mice infected with plasmodium yoelii 17xl or injected with lysed erythrocytes or plasma from p. yoelii infected mice or with p. falciparum culture supernatants. spleen/body weight ratio, numbers of nucleated spleen cells and immunoglobulin-containing and immunoglobulin-secreting cells increased prog ... | 1992 | 1284989 |
| experimental malaria in the cba/n mouse. | cba/n mice carry an x-linked, recessive gene, which results in the absence of a b cell subset, and is expressed primarily as an inability to respond to a certain class of thymus-independent antigens. we have examined the responses of these mice to the malaria parasite plasmodium yoelii and found that primary infections induced by this parasite are more severe and last longer in mice with x-linked defect than in normal controls. the decreased resistance of the defective mice is associated with a ... | 1979 | 387872 |
| the chemotherapy of rodent malaria. xlvii. studies on pyronaridine and other mannich base antimalarials. | the activities of mannich base antimalarials, including pyronaridine, have been explored against drug-sensitive (plasmodium berghei n) and chloroquine-resistant (plasmodium yoelii ns) rodent malaria parasites in vivo. lines of these parasites have been developed with resistance to pyronaridine, amodiaquine, or wr 228,258. the responses and patterns of cross-resistance of these lines to mannich bases and other blood schizontocides are inconsistent. it is concluded that some mannich bases may prov ... | 1992 | 1288426 |
| "antimalarial" medicinal plants and their impact on cell populations in various organs of mice. | we have investigated the effects of leaf and bark decoctions of ocimum gratissimum, azadirachta indica, morinda lucida and enantia chlorantha on (a) the course of plasmodium yoelii nigeriensis malaria (b) reticulocyte and haematocrit values and (c) nucleated cell numbers in the spleen, bone marrow, peritoneum, liver and peripheral blood of swiss albino mice. results obtained showed that normal mice infected with the parasite (10(4)/mouse) suffered fulminant parasitaemia which resulted in death, ... | 1992 | 1308080 |
| recombinant pseudorabies virus carrying a plasmodium gene: herpesvirus as a new live viral vector for inducing t- and b-cell immunity. | in balb/c mice, the sterile protective immunity induced by immunization with radiation-attenuated plasmodium yoelii sporozoites is eliminated by in vivo depletion of cd8+ t lymphocytes, suggesting that cytotoxic t lymphocytes (ctl) against malaria antigens expressed on infected hepatocytes are required for mediating this protective immunity. to produce a vaccine that would induce ctl against the p. yoelii circumsporozoite protein (cs), we constructed an attenuated pseudorabies virus (prv) contai ... | 1992 | 1323900 |
| aberrations in cerebral vascular functions due to plasmodium yoelii nigeriensis infection in mice. | plasmodium yoelii nigeriensis infection in mice caused an increase in uptake of 125i-labeled bovine serum albumin, 51cr-labeled erythrocytes and evans blue dye from peripheral circulation into the brain. isolated cerebral microvessels which were characterized in terms of their morphology under scanning electron microscope and enhancement of the specific activities of biochemical markers, viz. alkaline phosphatase, gamma-glutamyl transpeptidase, and monoamine oxidase, showed significant decrease ... | 1992 | 1356826 |
| cerebral ammonia levels and enzyme changes during plasmodium yoelii infection in mice. | ammonia, lactate and glutamate levels and the activities of glutamine synthetase (gs), glutamate dehydrogenase (gdh), glutaminase (gln), aspartate transaminase (ast), phosphofructokinase (pfk) and monoamine oxidase (mao) were compared in the brain tissue of normal and p. yoelii infected mice. the brain lactate increased by 96% at peak parasitaemia. cerebral ammonia also exhibited an increase in infected mice which was parasitaemia dependent, while glutamate remained almost unchanged. the brain g ... | 1992 | 1361009 |
| immunity to plasmodium yoelii and babesia microti: modulation by the cba/n x-chromosome. | cba/n mice carry an x-linked recessive defect expressed in cells of the b cell lineage. the major deficiency in these mice is an almost complete inability to respond to certain thymus-independent antigens, such as pneumococcal polysaccharide type iii (s iii). we have examined the responses of mice carrying the cba/n x-chromosome to the malaria parasite plasmodium yoelii and the piroplasm babesia microti. we have found that the duration and severity of these infections is increased in mice carryi ... | 1979 | 317444 |
| structure and expression of the gene for pv200, a major blood-stage surface antigen of plasmodium vivax. | molecular cloning and structure analysis of the gene encoding the pv200 protein of the sal-1 strain of plasmodium vivax revealed an overall identity of 34-37% when the deduced amino acid sequence was compared with the sequences of various major merozoite surface antigens of plasmodium falciparum, plasmodium yoelii and plasmodium chabaudi. when the sal-1 pv200 sequence was compared with the corresponding sequence from the belèm strain of p. vivax, it was found that the two merozoite surface antig ... | 1992 | 1371329 |
| the in vivo cytotoxic activity of cd8+ t cell clones correlates with their levels of expression of adhesion molecules. | cd8+ t cell clones specific for a defined epitope present in the circumsporozoite protein of plasmodium yoelii display striking differences in their in vivo antiplasmodial activity. the adoptive transfer of certain clones (ya23 and ya26) into naive mice inhibits by 90% or more the development of liver stages of malaria parasites and protects against malaria infection. the adoptive transfer of two other t cell clones (yb8 and ya15) results, respectively, in partial or no inhibitory activity on pa ... | 1992 | 1372647 |
| [localization of the antigen in erythrocytic stages of plasmodium yoelii by immuno-electron microscopy]. | in this study, the antigen recognized by the protective mcab m26-32 in erythrocytic stages of p. yoelii was localized by immuno-electron microscopy with lr whithe resin embedding and colloidal gold probe cytochemical techniques. the results indicated that the antigen which reacts specifically to mcab m26-32 was mainly localized within the cytoplasm of early and late trophozoites, schizonts and merozoites, being the common antigen of asexual blood stages of the plasmodium. the amount of the antig ... | 1992 | 1394891 |
| [roles of t cell subsets in the protective immunity of mice against plasmodium yoelii]. | balb/c mice which had developed protective immunity against plasmodium yoelii (p. y.) challenge were injected with anti-cd4 or anti-cd8 monoclonal antibody, and were then challenged again with p. yoelli. no impairment of protection was observed. cd8+t cells obtained from spleens of these mice were transferred to balb/c nude mice and induced partial protection, while transfer of cd4+t cells did not so. in p. yoelli-mouse model, the parasites invaded reticulocytes in the early infection, and the i ... | 1992 | 1394892 |
| characterization of plasmodium falciparum sporozoite surface protein 2. | immunization of mice with plasmodium yoelii sporozoite surface protein 2 (pyssp2) and circumsporozoite protein protects completely against p. yoelii. the amino acid sequence of pyssp2 suggested that the thrombospondin-related anonymous protein (trap) [robson, k. j. h., hall, j. r. s., jennings, m. w., harris, t. j. r., marsh, k., newbold, c. i., tate, v. e. & weatherall, d. j. (1988) nature (london) 335, 79-82] is the plasmodium falciparum homolog of pyssp2. we report data confirming that trap i ... | 1992 | 1409621 |
| [studies on the tissue schizonticide of malaria parasite: synthesis of derivatives of 2-substituted phenoxyprimaquine, 4-methylprimaquine and quinoxaline]. | 2-substituted phenoxy-, 4-methyl-6-methoxy-8-aminoquinolines and 7-methoxy-5-aminoquinoxaline were condensed with 1-phthalimido-bromo-alkane to yield 2-substituted phenoxy-, 4-methyl-6-methoxy-8-(1-phthalimidoalkyl)-aminoquinolines (compounds 7-10 and 15-20) and 7-methoxy-5-(1-phthalimidoalkyl)aminoquinoxalines (28-30) which were subsequently reacted with hydrazine hydrate to give 2-substituted phenoxy-, 4-methyl-6-methoxy-8-(1-aminoalkyl)-aminoquinolines (11-14 and 22-27) and 7-methoxy-5-(1-ami ... | 1992 | 1442068 |
| specific inflammatory cell infiltration of hepatic schizonts in balb/c mice immunized with attenuated plasmodium yoelii sporozoites. | we compared immunization of balb/c mice with radiation-attenuated versus killed sporozoites of the rodent malaria parasite, plasmodium yoelii. we employed a suboptimal schedule of only two immunizations, in expectation that some parasites might break through the resultant low level immunity and that it might thus be possible to study the response of the host against these 'breakthrough' schizonts. as a measure of protective immunity, we used histological means to determine the percentages of cha ... | 1992 | 1498082 |
| characterization of the gene encoding sporozoite surface protein 2, a protective plasmodium yoelii sporozoite antigen. | sporozoite surface protein 2 (ssp2) is a 140-kda, protective sporozoite surface protein from plasmodium yoelii distinct from the circumsporozoite protein (csp). a genomic clone containing the ssp2 gene was isolated and sequenced to determine its size, structural organization and deduced primary amino acid sequence. the coding sequence consists of a single, long open reading frame encoding 826 amino acids. the overall structure of ssp2 is similar to that of the csp, consisting of a central region ... | 1992 | 1501644 |
| a t cell clone directed at the circumsporozoite protein which protects mice against both plasmodium yoelii and plasmodium berghei. | clone b is a cytotoxic t cell clone induced by immunization with plasmodium yoelii sporozoites which recognizes an epitope on both the p. yoelii and plasmodium berghei circumsporozoite proteins. it is cd8, uses the v beta 8.1 tcr, and is kd restricted. when adoptively transferred, it protects mice against infection by both species of malaria sporozoites, and this protection is dependent on ifn-gamma. clone b cells are more broadly reactive and protective than previously described murine t cell c ... | 1992 | 1517574 |
| the use of nested pcr and southern blotting to confirm the presence of actin in plasmodium yoelli. | | 1991 | 1794544 |
| subcellular fractionation of the two organelle dnas of malaria parasites. | malaria parasites contain two extrachromosomal dnas, a 6 kb repetitive linear molecule which is assigned on the basis of its genetic content to the mitochondria, and a 35 kb transcriptionally active circular molecule whose intracellular location is not known. we used the polymerase chain reaction to detect and estimate the numbers of both molecules in sub-cellular fractions derived from the rodent parasite plasmodium yoelii. the two dna molecules were not coordinately partitioned by the fraction ... | 1992 | 1525866 |
| serological relationship of tumor necrosis factor-inducing exoantigens of plasmodium falciparum and plasmodium vivax. | exoantigens of plasmodium vivax-parasitized erythrocytes stimulated macrophages to secrete tumor necrosis factor, and antisera raised against the exoantigens inhibited this secretion. the antisera also inhibited the activity of plasmodium falciparum and plasmodium yoelii exoantigens, and conversely, antisera against the latter cross-reacted with the exoantigens of p. vivax. | 1992 | 1541540 |
| immunization with synthetic peptides containing a defined malaria epitope induces a highly diverse cytotoxic t lymphocyte response. evidence that two peptide residues are buried in the mhc molecule. | in the present study, we have explored ways of inducing a ctl response to a previously defined h-2kd mhc class i restricted epitope in the circumsporozoite (cs) protein of plasmodium berghei, and studied in detail the fine specificity of the response. we found that the s.c. injection of a variety of synthetic peptides emulsified in freund's adjuvant efficiently induced a specific ctl response in (balb/c x c57bl/6)f1 (h-2d x h-2b) mice. in contrast, balb/c mice responded only marginally, consiste ... | 1992 | 1541825 |
| detoxified exoantigens and phosphatidylinositol derivatives inhibit tumor necrosis factor induction by malarial exoantigens. | we have previously shown that malaria parasites liberate exoantigens which, through a phospholipid component, stimulate mouse macrophages to secrete tumor necrosis factor (tnf), which are toxic to d-galactosamine-sensitized mice, and which therefore might be involved in pathology. plasmodium yoelii exoantigens detoxified by dephosphorylation or digestion with lipases do not induce tnf production. however, these partial structures inhibited its production in response to the exoantigens, although ... | 1992 | 1563780 |
| comparison of the carboxy-terminal, cysteine-rich domain of the merozoite surface protein-1 from several strains of plasmodium yoelii. | | 1992 | 1620166 |
| antibodies against phosphatidylinositol and inositol monophosphate specifically inhibit tumour necrosis factor induction by malaria exoantigens. | the active component of the exoantigens of malarial parasites which stimulates macrophages to secrete tumour necrosis factor (tnf) has been shown to depend upon a phospholipid, the activity of which was blocked by phosphatidylinositol (pi) and inositol monophosphate (imp) in competitive inhibition studies. antisera made against the exoantigens of plasmodium yoelii, which inhibited their induction of tnf, were found by an elisa assay to contain antibody against several other phospholipids. howeve ... | 1992 | 1628898 |
| in vitro activity of cd4+ and cd8+ t lymphocytes from mice immunized with a synthetic malaria peptide. | in previous work, a t-helper epitope was mapped within the circumsporozoite protein of the murine malaria parasite plasmodium yoelii. a 21-mer synthetic peptide corresponding to this epitope (amino acid positions 59-79; referred to as py1) induced a specific t-cell proliferation in balb/c and c57bl/6 mice and provided help for the production of antibodies to peptides from the repetitive region, (gln-gly-pro-gly-ala-pro)n, of the p. yoelii circumsporozoite protein when mice were immunized with th ... | 1991 | 1680235 |
| cytotoxic t cells recognize a peptide from the circumsporozoite protein on malaria-infected hepatocytes. | irradiated malaria sporozoites can induce cd8+ t cells that are required for protection against infection. however, the parasite antigens targeted by this immune response are unknown. we have discovered a 16-amino acid epitope from the plasmodium yoelii circumsporozoite (cs) protein that is recognized by cytotoxic t cells from immune mice. lymphocytes stimulated with this peptide can kill p. yoelii liver stage parasites in vitro in an mhc-restricted, antigen-specific manner. thus, epitopes from ... | 1990 | 1689762 |
| immune responses to defined epitopes of the circumsporozoite protein of the murine malaria parasite, plasmodium yoelii. | we have investigated the immunogenicity of defined sequences of the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-ner synthetic peptide from the nonrepetitive region of the cs protein (position 59-79, referred to as py1) induced t cell proliferative responses in h-2d and, to a lesser extent, in h-2b mice. conversely, a synthetic peptide (referred to as py4) consisting of four (qgpgap) repeats of the p. yoelii cs protein, induced an antibody response only i ... | 1990 | 1695152 |
| complex transcription from the extrachromosomal dna encoding mitochondrial functions of plasmodium yoelii. | all tested members of genus plasmodium contain tandemly arrayed, transcribed, extrachromosomal dna with a unit length of 6.0 kb. this dna contains two open reading frames with potential to encode cytochrome c oxidase subunit i (cox1) and cytochrome b (cob) as well as fragments of rrna genes scattered on both strands. at least 10 discrete rna molecules transcribed during erythrocytic stages of a rodent malarial parasite, plasmodium yoelii, were recognized by the 6.0-kb dna probes. the rna molecul ... | 1990 | 1701017 |
| cytology and kinetics of microgametogenesis and fertilization in plasmodium yoelii nigeriensis. | the sexual development of the microgametocyte of plasmodium yoelii nigeriensis may be subdivided into microgametogenesis which includes exflagellation, dispersal of the gametes and fertilization. under our experimental conditions microgametogenesis takes about 8-15 min at 20 degrees c, the duration of this period being inversely related to temperature. exflagellation takes less than 1 min, subsequent dispersal of gametes may continue for 40 min. we find that exflagellation is totally inhibited i ... | 1975 | 1118188 |
| isolation and characterization of protective cytolytic t cells in a rodent malaria model system. | protective immunity against malaria is induced by immunization with irradiation-attenuated sporozoites. here we report the isolation of cytolytic t-cell (ctl) clones from balb/c (h-2d) mice immunized with either plasmodium berghei or plasmodium yoelii sporozoites. the epitopes recognized by these ctl can be mimicked by synthetic peptides corresponding to a homologous region in the cs proteins of both rodent malaria species. both peptides are recognized by the ctl in the context of the same mhc c ... | 1990 | 1704348 |
| peptide-primed cd4+ cells and malaria sporozoites. | we have mapped a t cell epitope in the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-mer synthetic peptide corresponding to the amino acid positions 59-79 (referred to as py1), induced specific proliferation in balb/c and c57bl/6 mice, and provided help for the production of antibodies to peptides from the repetitive region, (qgpgap)n, of the same cs protein, when mice were immunized with the py1 peptide conjugated to the repetitive peptide. long-term cd3+ ... | 1990 | 1704350 |
| characterization of a plasmodium falciparum epitope recognized by a monoclonal antibody with broad isolate and species specificity. | monoclonal antibody (mab) 7h8 raised against plasmodium yoelii reacted with a series of proteins from p. falciparum that range in molecular weight from 46 to 194 kda. by immunofluorescence assay, this mab reacted with all isolates of p. falciparum tested. mab 7h8 was used to screen a genomic expression library of asexual blood stage antigens of p. falciparum, malayan camp k+ and 7 independent clones were identified. these 7 clones were sequenced and the epitope recognized by mab 7h8 in the recom ... | 1990 | 1706114 |
| phospholipid-containing toxic malaria antigens induce hypoglycaemia. | hypoglycaemia is associated with severe malaria and is an important prognostic indicator. molecules liberated during overnight incubation of erythrocytes infected with plasmodium yoelii induce marked hypoglycaemia in normal mice, with a delayed time course compared with insulin; some, though weaker, activity could also be obtained by overnight incubation of uninfected erythrocytes. the active component shares many properties with the phospholipid-containing molecules which we have previously sho ... | 1992 | 1395089 |
| malarial toxic antigens synergistically enhance insulin signalling. | hypoglycaemia is a major complication of severe malaria [(1990) trans. roy. soc. trop. med. 84 (suppl. 2) 1-65], especially cerebral malaria, in which it is associated with increased mortality [(1990) lancet 336, 1039-1043; (1989) quart. j. med. (new series) 71, 441-459]; however, the mechanisms responsible have not been fully explained. preparations containing toxic malaria antigens (tma) released by blood stage plasmodium yoelii malaria parasites have been shown to induce hypoglycaemia in mice ... | 1992 | 1397320 |
| antigenic analysis of plasmodium yoelii liver stages by fluorescence antibody assays. | little is known about the immune response against liver stage antigens which were first described for plasmodium falciparum. in order to provide a basis for experimental studies, we analysed antigenically the liver stages of plasmodium yoelii using sera of restricted specificity. several distinct fluorescence patterns could be described in maturing liver forms. one pattern was identified as corresponding to antigens specific to the liver phase which are also species specific. another pattern cor ... | 1991 | 1724570 |
| il-6 induced by il-1 inhibits malaria pre-erythrocytic stages but its secretion is down-regulated by the parasite. | the capacity of il-6 to mediate the antiparasitic activity of il-1 on intrahepatic development of malaria parasite was demonstrated. the comparisons of il-6 levels in infected and noninfected hepatocyte cultures, either purified or enriched with nonparenchymal cells and stimulated by il-1 or il-6, indicate that subtle interactions exist between intrahepatocytic development of plasmodium yoelii and liver synthesis of il-6. during its intrahepatic multiplication, the parasite causes a decline in i ... | 1992 | 1727866 |
| host resistance to murine malaria in mice exposed to the adenosine deaminase inhibitor, 2'-deoxycoformycin. | resistance to infection with the nonlethal rodent malaria parasite plasmodium yoelii 17xnl (py 17xnl) is mediated by humoral, t-cell and accessory cell activity. the purpose this study was to profile host resistance to infection with this organism in mice exposed to 2'-deoxycoformycin (2dcf), a potent adenosine deaminase (ada) inhibitor. inhibition of ada activity by 2dfc results in defective t-cell function and either suppression or augmentation of the humoral response, depending on whether 2dc ... | 1991 | 1761363 |
| [effect of alpha-difluoromethylornithine on sporogony of plasmodium yoelii]. | the effect of alpha-difluoromethylornithine (dfmo) on the sporogony of p yoelii was studied by electron microscopy. dfmo sugar solution was fed to female mosquitoes. scanning electron microscopy (sem) revealed that the oocysts were smaller and the surface of oocysts was uneven as compared with control. transmission electron microscopy (tem) showed that cytoplasm of the affected oocysts contained vacuoles and the multilamellate structures increased. the number of matrix cavitations and deformatio ... | 1991 | 1781292 |
| activity of dihydrofolate reductase inhibitors on the hepatic stages of plasmodium yoelii yoelii in vitro. | the effects of the dihydrofolate reductase inhibitors proguanil and chlorproguanil, their active metabolites cycloguanil and chlorcycloguanil, and pyrimethamine, against the hepatic stages of plasmodium yoelii yoellii were investigated in cultured balb/c mouse hepatocytes. proguanil was inactive at concentrations of 10(-8) m, whereas the other compounds were fully active at this and lower concentrations. chlorcycloguanil was the most active compound and almost completely inhibited schizont devel ... | 1991 | 1801335 |
| [effect of nitroquine on protein synthesis of plasmodium yoelii in vitro]. | the erythrocytic stages of plasmodium yoelii (by 265 strain) were incubated with nitroquine (0.2 pmol.l-1 - 20 mumol.l-1), cycloheximide (0.1-10 nmol.l-1) and aminopterin (0.2 pmol.l-1 - 20 mumol.l-1) during 8 h in vitro. the results showed that the incorporation of [3h]-isoleucine into the protein by plasmodium yoelii was inhibited by nitroquine (0.2 pmol.l-1) and cycloheximide (0.1 nmol.l-1), the inhibitory effect of nitroquine (ic50 = 0.16 nmol.l-1) was 397 times higher than that of cyclohexi ... | 1991 | 1807087 |
| the effects of extracts of enantia chlorantha in malaria. | the aqueous extract of the plant enantia chlorantha was found effective in suppressing plasmodium yoelii infection in mice if given orally in drinking fluid at 0.2-150 mg ml-1, but not if given by oral cannulation or subcutaneously. the animals given the extract in their drinking fluid survived for over 60 days. the ethanolic extract also was found to be effective in eliminating the parasites when administered subcutaneously in doses of 0.05-0.5 mg g-1. the chemoprophylactic action of the aqueou ... | 1991 | 1811435 |
| the 235 kd rhoptry protein of plasmodium yoelii. | a 235 kd rhoptry protein produced by the malaria parasite, plasmodium yoelii is the target of antibodies that protect mice against blood-stage challenge with the virulent ym strain. in the protected animals the parasites are confined to reticulocytes and the course of parasitaemia is reminiscent of an avirulent 17x strain infection. the dna coding for the rhoptry protein has been identified as a multigene family containing at least four members. sequence analysis of short dna clones has identifi ... | 1991 | 1820696 |
| possible involvement of platelets in plasmodium yoelii nigeriensis malaria infection in mice. | the possible involvement of platelets in the pathogenesis of malaria was examined by monitoring the changes in platelet function (bleeding time [bt] and thrombin time [tt]) concomitantly with changes in packed cell volume (pcv) and erythrocyte infection rate (eir) in plasmodium yoelii nigeriensis infection in mice. in untreated plasmodium-infected mice, there was a progressive reduction (day 1-7) in bt from 120.0 +/- 12.6 s to 77.5 +/- 5.9 s (p less than 0.005), a reduction in tt from 26.8 +/- 1 ... | 1991 | 1823881 |
| protection against malaria by vaccination with sporozoite surface protein 2 plus cs protein. | the circumsporozoite (cs) protein has been the target for development of malaria sporozoite vaccines for a decade. however, immunization with subunit vaccines based on the cs protein has never given the complete protection found after immunization with irradiated sporozoites. balb/c mice immunized with irradiated plasmodium yoelii sporozoites produced antibodies and cytotoxic t cells against a 140-kilodalton protein, sporozoite surface protein 2 (ssp2). mice immunized with p815 cells that had be ... | 1991 | 1827210 |
| role of host cellular response in differential susceptibility of nonimmunized balb/c mice to plasmodium berghei and plasmodium yoelii sporozoites. | we found balb/c mice to be on the order of 2,000 times more susceptible to plasmodium yoelii than plasmodium berghei sporozoites, as measured by the ability of these sporozoites to differentiate into microscopically detectable hepatic schizonts in the livers of immunologically naive mice. one of the factors that determine the relative insusceptibility of mice to p. berghei sporozoites is the innate cellular inflammatory response that the mice mount after injection with sporozoites. the cellular ... | 1991 | 1855974 |
| tnf inhibits malaria hepatic stages in vitro via synthesis of il-6. | we examined the capacity of murine recombinant tumor necrosis factor (rmtnf) to induce an inhibitory effect at the hepatic stage on malaria induced by plasmodium yoelii sporozoites. when injected three times, 1.0 micrograms of rmtnf was found to protect 78% of mice against a sporozoite challenge. in contrast, whatever the dose and the schedule of administration, no inhibition was observed when purified hepatocyte cultures were infected with p. yoelii. the addition of non-parenchymal hepatic cell ... | 1991 | 1878339 |
| status of hepatic heme and heme oxygenase during plasmodium yoelii nigeriensis infection in mice. | plasmodium yoelii nigeriensis infection in albino mice caused a significant increase in hepatic heme level, the increase being concomitant with a rise in parasitemia. this elevated heme was found to be associated with all the subcellular fractions except the cytosol, where its content remained unaltered. activity of heme oxygenase, the key enzyme responsible for catabolism of heme, also increased progressively with rise in parasitemia. treatment of normal mice with cobalt chloride [60 mg (kg bod ... | 1991 | 1884769 |
| antimalarial antibodies of the immunoglobulin g2a isotype modulate parasitemias in mice infected with plasmodium yoelii. | previous studies have demonstrated the importance of antibodies in mediating immunity to malaria, but the relative contribution of the different immunoglobulin isotypes has not been assessed. in this study, hyperimmune plasma was generated against plasmodium yoelii and separated by protein a-sepharose chromatography into fractions containing immunoglobulin g1 (igg1), igg2a, igg2b, or igg3 antibodies and the remaining nonbinding plasma proteins, including igm. following concentration, the antimal ... | 1991 | 1894361 |
| plasmodium yoelii: antibody response in resistant and susceptible mouse strains. | the numbers of antigen-reactive antibody-secreting cells, levels of parasite antigen-specific serum antibodies and numbers of red blood cells staining positive for surface immunoglobulin were determined for susceptible and resistant mouse strains following infection with plasmodium yoelii 17x. as a control, these parameters also were measured using antigen prepared from normal red blood cells. the relatively susceptible c57bl/6 mice produced more antigen-specific antibody-secreting cells and had ... | 1991 | 1915739 |
| antibody recognition and isoelectrofocusing of antigens of the malaria parasite plasmodium yoelii. | inbred balb/c mice were either immunized with triton x-100-extracted antigens of blood-stage plasmodium yoelii or infected with p. yoelii and cured in three successive schedules. whereas the immunized balb/c became only partially protected from subsequent challenge infection with blood-stage p. yoelii, the convalescent mice acquired total immunity. when total p. yoelii antigen extract was resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and im ... | 1991 | 1937750 |
| activities of pefloxacin and ciprofloxacin against experimental malaria in mice. | we investigated the in vivo antimalarial activities of pefloxacin and ciprofloxacin in swiss albino mice infected intravenously with 5 x 10(6) plasmodium yoelii n67 parasites 1 h before treatment. groups of 20 mice received a subcutaneous injection of 40, 80, or 160 mg of ciprofloxacin or pefloxacin per kg of body weight every 8 h for 3 days. parasitologic activity was assessed on day 4, and survival was assessed on day 21. control mice had a fulminant course with a parasitemia of 61.3% +/- 12.1 ... | 1990 | 1708223 |
| generation of a cytotoxic t-lymphocyte response using a salmonella antigen-delivery system. | we have constructed a general-use vector for the cloning and stable expression of foreign genes in the chromosome of attenuated salmonella typhimurium. using this chromosomal expression vector (cev), we expressed the circumsporozoite (cs) gene of the mouse malaria plasmodium yoelii in an aroa s. typhimurium strain. mice immunized with cs-expressing salmonella recombinants mount a cs-specific cytotoxic t-lymphocyte (ctl) response. this is the first demonstration that attenuated salmonella can eli ... | 1990 | 2089224 |
| active and passive immunization against plasmodium yoelii sporozoites. | three subunit vaccines based on the major repeat, (qgpgap)n, and flanking regions of the plasmodium yoelii circumsporozoite protein were designed, produced, and tested. all were immunogenic, but none gave consistent protection against a 40-200 sporozoite challenge. to demonstrate that antibodies to p. yoelii cs protein could provide protection we established a passive transfer model. passive transfer of nys1, an igg3 mab against the p. yoelii cs protein, protected 100% of mice against challenge ... | 1990 | 1709834 |
| cd8+ cytolytic t cell clones derived against the plasmodium yoelii circumsporozoite protein protect against malaria. | immunization of balb/c mice with radiation-attenuated plasmodium yoelii sporozoites induces cytotoxic t lymphocytes (ctl) specific for an epitope located within the amino acid sequence 277-288 of the p. yoelii circumsporozoite (cs) protein. several cd8+ ctl clones were derived from the spleen cells of sporozoite-immunized mice, all displaying an apparently identical epitope specificity. all the clones induced high levels of cytolysis in vitro upon exposure to peptide-incubated mhc-compatible tar ... | 1991 | 1716146 |
| evaluation of vaccines designed to induce protective cellular immunity against the plasmodium yoelii circumsporozoite protein: vaccinia, pseudorabies, and salmonella transformed with circumsporozoite gene. | in an attempt to induce a protective cytotoxic t-cell mediated immunity against sporozoites of plasmodium yoelii, the gene encoding the p. yoelii circumsporozoite (cs) protein was engineered into three live vectors: vaccinia, attenuated pseudorabies, and attenuated salmonella typhimurium. balb/c mice were immunized with 1-4 doses of 10(8) pfu of the vaccinia construct (ip), 3 doses of 10(5), 10(6) or 10(7) pfu of pseudorabies construct (iv), and 3 doses of 10(9) salmonella transformants (orally) ... | 1990 | 2094576 |
| towards the design of heterovalent anti-malaria vaccines: a hybrid immunogen capable of eliciting immune responses to epitopes of circumsporozoite antigens from two different species of the malaria parasite, plasmodium. | the peptide cs.t3, corresponding to residues 378-398 of the plasmodium falciparum (pf) circumsporozoite (cs) protein sequence (except with cysteines 384 and 389 replaced by alanines), has been found to be almost universally recognized by human and mouse t lymphocytes. when colinearly linked to the repetitive b-lymphocyte-specific epitope (asn-ala-asn-pro)n of pf cs protein, cs.t3 induces t-helper activity for an anti-(asn-ala-asn-pro)n antibody response in mice of different haplotypes. we constr ... | 1991 | 1721043 |
| identification of a common plasmodium epitope (cpe) recognised by a pan-specific inhibitory monoclonal antibody. | a plasmodium falciparum genomic expression library was screened with a monoclonal antibody produced from mice infected with plasmodium yoelii. eleven unique clones were isolated all of which contained the sequence nknd, iknd or kknd. this sequence was confirmed as the epitope of m26-32 by testing a series of overlapping peptides and the allowable substitutions determined by testing the binding of m26-32 to peptides containing all possible single amino acid replacements of nknd. potential epitope ... | 1991 | 1723149 |
| adoptive transfer of cd8+ t cells from immune animals does not transfer immunity to blood stage plasmodium yoelii malaria. | the malaria parasite, plasmodium yoelii 17x, causes a self-limited, nonlethal infection characterized, in the blood stage, by preferential invasion of reticulocytes. previous studies have suggested that immunity to the blood stage infection may be related to enhanced levels of class i mhc ag on the parasitized reticulocyte surface and can be adoptively transferred to immunodeficient mice by immune cd8+ t cells in the absence of cd4+ t cells. to further examine the mechanisms of cd8+ t cell invol ... | 1990 | 1967271 |
| cd4+ t cells play a major role for igm and igg anti-dna production in mice infected with plasmodium yoelii. | the infection by a non-lethal strain of plasmodium yoelii induces the formation of autoantibodies such as anti-dna and anti-sm antibodies in mice. the extent of the relative increase in serum levels of igm and igg anti-dna and anti-sm antibodies and their kinetics were found to be similar to those of anti-hapten antibodies and of total igm and igg levels. this strongly suggested that anti-dna and anti-sm autoantibody responses observed in malaria-infected mice are a result of polyclonal activati ... | 1990 | 1968798 |
| cellular mechanisms in immunity to blood stage infection. | we studied mechanisms of immunity to blood stage infection in the mouse malarias plasmodium vinckei and plasmodium yoelii 17x. infection with p. vinckei was uniformly lethal, whereas p. yoelii 17x caused a self-limited, nonlethal infection. transfer of immune cd4+ t cells conferred protection against p. yoelii in nude mice. previous studies by others had suggested that immunity to p. yoelii may be related to mhc class i expression on reticulocytes and found that cd8+ t cells alone transferred pr ... | 1990 | 1980907 |
| hepatic phase of malaria is the target of cellular mechanisms induced by the previous and the subsequent stages. a crucial role for liver nonparenchymal cells. | both the sporozoites and the erythrocytic stages can modulate the hepatic phase by cytokines, notably ifn-gamma, tnf and il-6, either directly or as a result of a cascade of events, and by mhc-restricted and antibody-dependent cell-mediated cytotoxicity. the role played by cd8+ t cells in inducing protective immunity against pre-erythrocytic stages is clearly established. the potential interest of triggering peptide-primed cd4+ t cells has to be considered regarding protection. indeed, cd4+ t ce ... | 1990 | 1980910 |
| monoclonal, but not polyclonal, antibodies protect against plasmodium yoelii sporozoites. | one of the primary strategies for malaria vaccine development has been to design subunit vaccines that induce protective levels of antibodies against the circumsporozoite (cs) protein of malaria sporozoites. in the plasmodium yoelii mouse model system such vaccines have been uniformly unsuccessful in protecting against sporozoite-induced malaria. to demonstrate that antibodies to p. yoelii cs protein could provide protection we established a passive transfer model. passive transfer of navy yoeli ... | 1991 | 1988490 |
| plasmodium yoelii: quantification of the exoerythrocytic stages based on the use of ribosomal rna probes. | | 1991 | 1993458 |
| a spleen is not necessary to resolve infections with plasmodium yoelii. | the role of the spleen in resistance to infections with nonlethal plasmodium yoelii 17x is dependent upon the genotype of the host. thus, dba/2 (d2) mice infected with p. yoelii 17x were not adversely affected by removal of the spleen, while splenectomized c57bl/6 (b6) or balb/c mice failed to resolve their infections and eventually died. the levels of parasitemia were lower in splenectomized mice compared to intact controls; however, splenectomized mice became as anemic as did spleen-intact con ... | 1991 | 1996740 |
| immunization and protection against malaria during murine pregnancy. | normal and immune mice were evaluated for their ability to resist infection to the rodent malaria parasite, plasmodium yoelii, during pregnancy. parasitemia levels were slightly higher and time-to-death shorter in the nonimmunized pregnant group infected with virulent parasites relative to virgin controls. subinoculation experiments revealed that numerous virulent organisms were present in the placentas of unprotected gravida but were absent from the fetal livers of their conceptuses. it was als ... | 1991 | 2012261 |