| some studies on acquired immunity to plasmodium chabaudi and plasmodium yoelii in mice. | | 1988 | 3217627 |
| the plasma membrane and mitochondrial membrane potentials of plasmodium yoelii. | 1. the plasma membrane potential and the mitochondrial membrane potential of p. yoellii was examined by fluorescence microscopy using rhodamine 123 and by transmembrane distribution of tetraphenylphosphonium. 2. the mitochondrion of p. yoelii, free of gametocyte stage, maintained a high negative inside membrane potential. 3. deprivation of glucose in incubation medium largely abolished the plasma membrane potential but not the mitochondrial membrane potential. 4. studies with metabolic inhibitor ... | 1988 | 3224510 |
| effect of temperature on erythrocyte-free plasmodium yoelii. | | 1988 | 3252761 |
| [some ultrastructural characteristics of plasmodium yoelii yoelii in erythrocytic schizogony and gametocytosis]. | | 1988 | 3253022 |
| single dose curative and prophylactic efficacy of antimalarial drugs against multi-resistant plasmodium yoelii nigeriensis. | | 1988 | 3256563 |
| selection of plasmodium yoelii nigeriensis resistant to triple drug combination (sulphadoxine/pyrimethamine/mefloquine) and its response to other antimalarials. | | 1988 | 3266603 |
| variation among circumsporozoite protein genes from rodent malarias. | we investigated the effect of long term passage of parasites in naive animals on the circumsporozoite protein (csp) gene of plasmodium yoelii. the csp gene sequence was determined from a non-lethal cloned line of p. yoelii and compared to the csp gene sequence from a lethal strain of p. yoelii. the two parasite lines were originally derived from the same isolate, but were separated 17 years ago followed by continued passage. the sequence of the csp gene and its surroundings from the non-lethal l ... | 1988 | 3287156 |
| malarial parasites induce tnf production by macrophages. | mouse peritoneal macrophages incubated with erythrocytes infected with non-lethal or lethal variants of plasmodium yoelii or with p. berghei, in the presence of polymyxin b to exclude the effects of any contaminating endotoxin, secreted a cytotoxic factor into the supernatant that was shown to be tumour necrosis factor (tnf). no differences were observed in the ability of the three types of parasite to induce tnf production, which was maximal in the range of 0.2-5 infected erythrocytes per macro ... | 1988 | 3292408 |
| a rapid method for screening antibodies to plasmodium yoelii liver stages by immunofluorescence. | | 1987 | 3325624 |
| leishmania mexicana: effect of concomitant malaria on cutaneous leishmaniasis. development of lesions in a leishmania-susceptible (balb/c) strain of mouse. | effect of concomitant malaria on cutaneous leishmaniasis. development of lesions in a leishmania-susceptible (balb/c) strain of mouse. experimental parasitology 65, 269-276. symptoms of human leishmaniasis vary greatly, ranging from cryptic infections to cases with fatal sequelae. factors regulating the severity of the disease are largely undetermined. malaria coincides geographically with leishmaniasis in many areas and the immunosuppressive effects of malaria are well documented. it is therefo ... | 1988 | 3350106 |
| inbred mice infected with plasmodium yoelii differ in their antimalarial immunoglobulin isotype response. | antibodies are known to be important in mediating malarial immunity, but the influence of the various immunoglobulin isotypes on parasite elimination is unclear. the purpose of this study was to provide basic information on the induction of isotype expression in genetically different mice during primary malaria. parasitaemias and the serum antimalarial igm, igg1, igg2, igg3 and iga antibody titres measured in a radioimmunoassay were followed in outbred and 11 inbred strains of mice infected with ... | 1988 | 3353128 |
| immunoregulation in murine malaria. susceptibility of inbred mice to infection with plasmodium yoelii depends on the dynamic interplay of host and parasite genes. | inbred and h-2 congenic mouse strains were tested for their ability to resist infections with the non-lethal 17x or with the lethal ym isolates of plasmodium yoelii. dba/2 and b10.d2 mice, which best resisted infections with non-lethal p. yoelii, were exquisitely susceptible to infection with lethal isolates of this malaria species. in contrast, b6 and b10 mice, which were susceptible to infection with non-lethal p. yoelii, were resistant to infection with the lethal isolates. this reversal of h ... | 1988 | 3379305 |
| an immunogenic antigen of murine plasmodium yoelii 17x associates with class i mhc glycoproteins. | reticulocytes infected with the non-lethal variant of plasmodium yoelii 17x (py17x-nl) express elevated levels of class i, but not class ii, mhc ag when compared with non-parasitized reticulocytes. in contrast, class i ag are not detectable on erythrocytes parasitized by the lethal variant py17x-l. in addition, the responder status of various inbred strains of mice to py17x-nl has been shown to positively correlate with the levels of class i mhc antigens expressed on py17x-nl parasitized red blo ... | 1988 | 3379306 |
| [effects of cyclophosphamide on the development of exo-erythrocytic forms of plasmodium yoelii in rats]. | | 1987 | 3447778 |
| in vivo testing of subunit vaccines against malaria sporozoites using a rodent system. | to test the putative in vivo protective effects of antibodies to circumsporozoite (cs) protein repeats against malarial infection, different strains of mice were immunized against various repetitive regions of the plasmodium yoelii cs protein in the form of synthetic peptides conjugated to keyhole limpet hemocyanin. complete freund's adjuvant or saponin was used as adjuvant. when vaccinated mice were challenged with 500 sporozoites almost all animals became infected. there were no significant pr ... | 1987 | 3479809 |
| suppression of b cell differentiation by 2,3,7,8-tetrachlorodibenzo-p-dioxin. | acute exposure of adult mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd) results in a selective suppression of proliferating cells of the immune system, including hematopoietic stem cells and b cells. suppression of b cell-mediated or humoral immunity, in turn, results in altered host resistance to the parasite plasmodium yoelii, a malaria model. data presented in this study demonstrate a direct effect of tcdd on cultured lymphoctes resulting in a selective inhibition of the differentiation of ... | 1986 | 3486342 |
| immunity to plasmodium yoelii: kinetics of the generation of t and b lymphocytes that passively transfer protective immunity against virulent challenge. | adoptive immunization of a/tru mice with splenic b cells or t cells from syngeneic donors with a primary, nonvirulent, plasmodium yoelii (17x) infection confers on these recipients the capacity to resist a challenge infection with a virulent strain (ym) of p. yoelii. unfractionated spleen cells as well as spleen cells enriched for t or b cells capable of transferring protective immunity were detected as early as day 7 of the primary nonvirulent infection, and reached peak levels on day 14. splee ... | 1986 | 3489552 |
| the chemotherapy of rodent malaria xli. causal prophylaxis. part v. effect of mefloquine on exoerythrocytic schizogony in plasmodium yoelii yoelii. | previous studies using mefloquine in rodents have suggested that this compound has no effect on pre-erythrocytic schizogony. in the present study, direct observations on 46-hour-old pre-erythrocytic schizonts of p. yoelii in the liver of rats have shown that mefloquine does induce recognizable changes in the peripheral, enzyme-containing vesicles but that these are insufficient to hinder the maturation of the parasites, thus confirming that this compound has no causal prophylactic value. | 1986 | 3499879 |
| use of a two-sited monoclonal antibody assay to detect a heat-stable malarial antigen in the sera of mice infected with plasmodium yoelii. | antigens, circulating in the blood during malarial infections, have been implicated in immune protection, immunosuppression, and immune-complex formation. we used a monoclonal antibody (mab 7h8) to identify an antigen (ag-7h8) in the sera of mice infected with plasmodium yoelii. the major form of the antigen has a molecular weight of approximately 120,000 in p. yoelii, with minor components of 220,000; 65,000 to 75,000; and 45,000. ag-7h8 remains antigenic after boiling for 5 min. a two-sited as ... | 1986 | 3512438 |
| [isoenzyme typing of strains of plasmodium berghei and plasmodium yoelii]. | | 1986 | 3530087 |
| studies of murine malaria antigens using monoclonal antibodies. production, selection, and characterization of antibodies. | a panel of ten monoclonal antibodies made against plasmodium chabaudi and plasmodium yoelii infected mouse erythrocytes were used for characterization of antigens present in murine malaria. screening of the antibodies in elisa with different fractions of infected erythrocytes revealed both species-specific and fraction-specific monoclonal antibodies (mabs), but also mabs cross-reacting between the species. two mabs bound normal erythrocyte components. subcellular localization of the target antig ... | 1986 | 3535284 |
| qinghaosu resistance in rodent malaria. | resistance to qinghaosu (artemisinin) developed rapidly in a chloroquine-resistant line of plasmodium yoelii (ns) passaged in mice, but was not produced in chloroquine-sensitive p. berghei. development of resistance took place in an apparently stepwise fashion. after removal of drug selection pressure some resistance was lost which was regained rapidly within three passages when drug pressure was reapplied. the resistant qs line was cross-resistant to two reduced derivatives of artemisinin but n ... | 1986 | 3541309 |
| macrophage cytotoxicity in lethal and non-lethal murine malaria and the effect of vaccination. | we investigated the development of cell-mediated immunity in lethal and non-lethal malarial infections by assaying the cytotoxic activity of spleen cells for l929 tumour cells at different times after infection of mice with the lethal p. berghei, a lethal variant of plasmodium yoelii and the non-lethal p. yoelii and p. chabaudi. in all cases the cytotoxicity increased to a peak during the first week and then diminished but the time of the peak varied with the infection; its activity was lowest w ... | 1986 | 3542317 |
| nucleoside permeation in mouse erythrocytes infected with plasmodium yoelii. | in normal mouse erythrocytes, nucleoside permeation was almost completely blocked in the presence of binding site-saturating concentrations of nitrobenzylthioinosine, whereas permeation in erythrocytes infected with the malarial parasite, plasmodium yoelii, was substantial under these conditions, suggesting the presence of a permeation mechanism of low sensitivity to nitrobenzylthioinosine in the infected cells. binding sites for nitrobenzylthioinosine were more numerous on infected erythrocytes ... | 1987 | 3606597 |
| a method for monitoring the viability of malaria parasites (plasmodium yoelii) freed from the host erythrocytes. | the viability of erythrocyte-free malaria parasites (plasmodium yoelii) was assessed with the cationic fluorescent dye, rhodamine 123 (r123). parasites were freed from infected mouse erythrocytes either by saponin lysis or by tris-ammonium chloride lysis and incubated with r123 at 37 degrees c. the parasite-associated dye was extracted with iso-butanol and measured with a fluorescent spectrophotometer. r123 accumulated intensely in free parasites prepared by saponin lysis but only weakly in thos ... | 1987 | 3617188 |
| simple and rapid staining for detection of entamoeba cysts and other protozoans with fluorochromes. | three fluorochromes were applied to stain various parasitic protozoans. by double staining with 4',6-diamidino-2-phenylindole and propidium iodide, differentiation of the nuclei from the cytoplasm can easily be achieved within several seconds. the chromatoid bodies in entamoeba cysts were stained bright red. plasmodium yoelii at all stages except late trophozoites and young gametocytes was easily identified. in the oocysts of cryptosporidium sp., the nuclei and cytoplasm of the sporozoites fluor ... | 1987 | 3626134 |
| effect of plasmodium yoelii nigeriensis infection and chloroquine on the hepatic mixed function oxidase system of mice. | plasmodium yoelii nigeriensis infection in albino mice significantly altered the hepatic microsomal mixed function oxidase system. cytochrome p-450 (the terminal monooxygenase) and other monooxygenases, viz. aniline hydroxylase, aminopyrine-n-demethylase and benzo(a)pyrene hydroxylase were significantly lowered while microsomal heme showed 4-fold increase at 80% parasitaemia. noticeable impairment in the other components like nadh:cytochrome b5 reductase, nadph:cytochrome c reductase, cytochrome ... | 1987 | 3627173 |
| [inhibition of the infectivity of plasmodium gametocytes by the serum of the parasite host. perfecting an experimental model]. | in the course of experimental malarial infections the infectivity of the gametocytes falls abruptly and at an early stage of the infection. this phenomenon is independent of the production of circulating antibodies. with plasmodium yoelii nigeriensis infecting the white mouse, the maximum infectivity of gametocytes for anopheles stephensi occurs on day 2, and on day 5 no more oocysts develop in the mosquito. the behaviour of the plasmodial strain in the mouse and particularly the "crisis" phenom ... | 1987 | 3662325 |
| elucidation of the receptors in macrophage and plasmodium yoelii interactions. | binding of hyperimmune serum opsonized merozoites of plasmodium yoelii nigerensis to trypsinized macrophages suggested it to be mediated by fcii receptor. receptor blocking inhibition with monoclonal antibody 2.4g2 directed against fc receptor for igg1/igg2b provided evidence that fc delta 2b on macrophage played an important role in the merozoite-macrophage interactions. in addition, a neuraminidase sensitive receptor was noted to mediate the binding of p. yeelii merozoites in the absence of se ... | 1987 | 3666847 |
| comparison of fast (one-step) and interrupted slow cooling methods using a range of intracellular and extracellular cryoprotectants for the freeze-preservation of plasmodium yoelii-infected mouse erythrocytes. | several cryoprotectants were compared using two different cooling procedures for the cryopreservation of both normal and plasmodium yoelii-infected mouse erythrocytes. fast cooling to -196 degrees c by direct plunge into liquid nitrogen followed by rapid thawing in a 37 degree c water bath protected uninfected and parasitized erythrocytes against freeze-thaw damage significantly better than an interrupted slow cooling procedure in which cells were frozen to -70 degrees c at a rate of -1 degree c ... | 1986 | 3726993 |
| prenatal determination of obesity, tumor susceptibility, and coat color pattern in viable yellow (avy/a) mice. the yellow mouse syndrome. | maturity-onset obesity and elevated circulating insulin levels are characteristic of some, but not all, mice bearing the viable yellow mutation (avy) at the agouti locus. the expression of the avy/a genotype in individual mice, which become obese and which remain lean is determined during prenatal development by as yet unidentified conditions in the dam's reproductive tract. one avy/a phenotype is identified by a mottled yellow coat and characterized by adult obesity, elevated circulating insuli ... | 1986 | 3734404 |
| mechanisms of splenic control of murine malaria: reticular cell activation and the development of a blood-spleen barrier. | by complex stromal responses, the spleen controls the course of nonlethal plasmodium yoelii murine malaria. the course of disease may be divided into four phases. in the immediate postinfective phase, lasting several days, the filtration beds of the spleen are open. parasitized and nonparasitized erythrocytes, many plasma cells, lymphocytes, and macrophages are sequestered from the blood; and most or all of the parasitized erythrocytes are phagocytized. in the following precrisis phase, approxim ... | 1986 | 3739951 |
| evasion of macrophage microbicidal mechanisms by mature sporozoites of plasmodium yoelii yoelii. | sporozoites of plasmodium yoelii yoelii were incubated for 40 min with balb/c peritoneal macrophages in the presence of nitro-blue tetrazolium (nbt). while immature oocyst sporozoites triggered the macrophage respiratory burst, as visualized microscopically by the localized reduction of nbt to insoluble formazan, 97.6% of mature salivary gland sporozoites did not induce such a response. the macrophage oxidative response was also induced by 82.7% of heat-inactivated and 95.7% of trypsin-treated s ... | 1986 | 3748614 |
| phosphatidylcholine liposomes as effective adjuvant for vaccination of mice against plasmodium yoelii. | | 1986 | 3770834 |
| plasmodium yoelii: induction of attenuated mutants by irradiation. | when erythrocytic forms of plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to x rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 krad). a suspension of 5 x 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. the infections of 8 mice of the 11 ... | 1986 | 3780926 |
| [spleen cell antibody-dependent cell-mediated cytotoxicity (adcc) in mice infected with plasmodium yoelii yoelii]. | | 1986 | 3791586 |
| an increase in water content of mouse erythrocytes infected with plasmodium yoelii. | mean cell volume and mean cell water content were examined in plasmodium yoelii-infected mouse erythrocytes by gas chromatography and 3h-sucrose. mean cell volume increased by 16% in infected erythrocytes with late trophozoites and schizonts. mean cell water content further increased by 23% in the infected erythrocytes. measurement of the erythrocyte potassium and sodium concentrations by an atomic absorption spectrophotometer revealed that the infected erythrocytes contained highly elevated sod ... | 1986 | 3810787 |
| comparative susceptibilities of anopheles quadrimaculatus mutants to plasmodium yoelii. | four homozygous mutant stocks and a wild-type stock (orlando) of anopheles quadrimaculatus were compared for susceptibility to plasmodium yoelii. the mutant stocks, rose eye (ro) and red stripe (strd), had the same level of susceptibility as the control stock (orlando), but q2 (homozygous for brown body and nonstripe) and rose eye q2 (roq2), were significantly less susceptible. body size of the adult mosquitoes had no effect on susceptibility. | 1985 | 3880267 |
| distribution of immunoglobulin isotypes in the nonspecific b-cell response induced by infection with plasmodium chabaudi adami and plasmodium yoelii. | the nonspecific b-cell response induced by infecting mice with two nonlethal malaria parasites, plasmodium chabaudi adami and plasmodium yoelii, was analyzed in an isotype-specific reverse plaque assay. our results showed different isotypic patterns in the two infections, although cells secreting immunoglobulin of all isotypes were increased to some extent. p. yoelii induced large increases in secreting cells of all isotypes; igg2a-secreting cells were increased out of proportion to those of the ... | 1985 | 3881190 |
| an antigen of plasmodium yoelii that translocates into the mouse erythrocyte membrane upon entry into the host cell. | monoclonal antibodies against the rodent malaria parasite, plasmodium yoelii, have been prepared and characterized by indirect immunofluorescence on acetone-fixed infected mouse erythrocytes. the antibody of clone k2 reacted strongly with late trophozoites and schizonts, whereas it did so weakly and diffusely with ring forms and early trophozoites. strong fluorescence was confined to granular structures in schizonts and merozoites. parasites that invaded erythrocytes in vitro lost the strong flu ... | 1985 | 3894385 |
| monoclonal anti-gamete antibodies prevent transmission of murine malaria. | three monoclonal antibodies prepared using spleen cells from mice immunized with microgametes of plasmodium yoelii nigeriensis were tested for their ability to block transmission of the infection. two of them agglutinated microgametes and blocked transmission, this effect being antibody-dose dependent. the third monoclonal used alone was ineffective in both these assays although it stained gametocytes and microgametes by immunofluorescence in the same way as the protective monoclonals. however, ... | 1985 | 3912705 |
| [cultivation of exo-erythrocytic schizonts of rodent plasmodium in hepatocytes: a new experimental model for chemotherapy of malaria]. | an in vitro experimental model using primary cultures of laboratory bred thamnomys gazellae's hepatocytes and plasmodium yoelii yoelii' sporozoites was set up for chemotherapeutic studies. the surface of the culture was reduced (0.5 cm) and allowed the rapid performance and analysis of schizonticide activity tests, with a reduced biological material (rodents, anopheles, sporozoites). fifteen compounds were tested. when activity of molecules is known in vivo, both results in vivo and in vitro are ... | 1985 | 3933782 |
| virulence of plasmodium yoelii line ym is caused by altered preference for parasitized and unparasitized immature and mature erythrocytes. | in the phase of beginning and continuing nearly complete parasitization of all immature erythrocytes and marked multiple parasitization of immature erythrocytes, less merozoites of the virulent type are lost in the population of parasitized and unparasitized immature erythrocytes, more merozoites invade mature erythrocytes. this behaviour determines the rapidly lethal course of the infection. it appears to be related to altered properties of the merozoite surface. virulent parasites do not show ... | 1985 | 4001767 |
| alteration of bone marrow cell cycle kinetics by diphenylhydantoin: relationship to folate utilization and immune function. | female b6c3f1 mice were administered the anticonvulsant drug diphenylhydantoin (dph) for 1 to 4 weeks by gavage at doses of 25 to 200 mg/kg. none of the dosing regimens caused toxicological manifestations other than hepatomegaly. evaluation of the immune status of the drug-treated mice revealed no alteration of cellular immunity, measured by delayed hypersensitivity response and lymphocyte responsiveness to mitogens or allogeneic leukocytes. humoral immunity, as measured by serum immunoglobulin ... | 1985 | 4009505 |
| vaccination with purified microgamete antigens prevents transmission of rodent malaria. | malaria vaccination with preparations of microgametes has been shown to inhibit transmission of plasmodium spp. to the mosquito vectors of avian, rodent and simian parasites. this transmission-blocking immunity results from the induction of microgamete-agglutinating antibodies in the vaccinated host which, when ingested in a mosquito blood meal, react with exflagellating microgametes in the midgut to prevent fertilization and oocyst development. here we have passively transferred the immunity wi ... | 1985 | 4022122 |
| a comparison of the pyrimethamine and cycloguanil sensitivities of the pre-erythrocytic and erythrocytic stages of drug-sensitive and -resistant strains of plasmodium yoelii. | the cycloguanil and pyrimethamine sensitivities of the pre-erythrocytic and erythrocytic stages of a drug-sensitive and drug-resistant strain of plasmodium yoelii have been compared. with both compounds, and in both parasite strains, the pre-erythrocytic stages were more sensitive to inhibition than were the erythrocytic stages. in the resistant strain the increase in the level of drug tolerance in the erythrocytic stages was paralleled by a corresponding loss of sensitivity in the pre-erythrocy ... | 1985 | 4026437 |
| [observation on the susceptibility of anopheles dirus to plasmodium yoelii yoelii]. | | 1985 | 4053316 |
| [concentration and isolation of schizonts and merozoites of plasmodium yoelii yoelii]. | | 1985 | 4053319 |
| the role of cell-mediated immune responses in resistance to malaria, with special reference to oxidant stress. | asexual blood forms of malaria parasites are microaerophilic and sensitive to oxidant stress. plasmodium falciparum and some other species of malaria parasites undergo schizogony attached to endothelial cells of postcapillary venules, where oxygen tensions are low. acquired immune responses to all forms of malaria parasites so far investigated are thymus dependent. animals deprived of t lymphocytes do not recover from the infections and cannot be immunized against malaria parasites. in contrast, ... | 1983 | 6100538 |
| the role of the kupffer cell in the infection of rodents by sporozoites of plasmodium: uptake of sporozoites by perfused liver and the establishment of infection in vivo. | the uptake of plasmodium yoelii nigeriensis sporozoites by isolated perfused rat liver was very rapid and efficient. 67% of the initial load was removed from the perfusion media in the first passage through the liver, and 95% after 15 min of perfusion. much of the uptake was explained by mechanical trapping in the liver. up to 75% of the sporozoite load was retained after 15 min both by heat killed liver and liver cooled to 4 degrees c, therefore at least 20% of the sporozoite uptake in perfused ... | 1982 | 6122359 |
| antimalarial activity of inhibitors of adp-ribosyl transferase against plasmodium yoelii infection in mice. 1. preliminary data. | | 1982 | 6128898 |
| the chemotherapy of rodent malaria, xxxiv. causal prophylaxis part iii: ultrastructural changes induced in exo-erythrocytic schizonts of plasmodium yoelii yoelii by primaquine. | wistar rats were injected intravenously with sporozoites from anopheles stephensi infected with plasmodium yoelii yoelii. the animals were subsequently treated with primaquine at doses of 30, 50 or 100 mg kg-1 at various times. liver biopsies were made and the exoerythrocytic schizonts examined by light and electron microscopy between 45 and 50 hours. the action of the drug appeared to be principally on the parasite mitochondria, the membranes of which became thickened, then proliferated into mu ... | 1983 | 6140901 |
| protective antigens of rodent and human bloodstage malaria. | bloodstage malaria parasites are antigenically complex, but individual antigens can be identified and analysed using monoclonal antibodies. two monoclonal antibodies that recognize a 235 000 molecular mass plasmodium yoelii rhoptry protein provide some protection when injected into mice against a challenge infection. the purified rhoptry protein also provides protective immunity against p. yoelii ym when used to vaccinate mice and fulminating infections are converted into self-limiting, reticulo ... | 1984 | 6151681 |
| monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii. | eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii. specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythr ... | 1981 | 6166558 |
| immunodepression of thymus-independent response to dextran in mouse malaria. | the thymus-independent antibody response to the alpha 1-6 epitope of dextran b512 was depressed strongly during acute non-lethal plasmodium yoelii yoelii malaria, but not during low-grade chronic plasmodium berghei infection. in the acute infection, which is self-limiting, the duration of severe immunodepression was short and was seen only in mice immunized at or around the time of peak parasitaemia. mice primed at this time responded normally to challenge 20 days later: thus the primary exposur ... | 1981 | 6167386 |
| plasmodium yoelii: comparison of indirect immunofluorescence and radioimmunoassay for detecting monoclonal antibodies to malaria. | | 1982 | 6177548 |
| staining of plasmodium yoelii-infected mouse erythrocytes with the fluorescent dye rhodamine 123. | the cationic permeant fluorescent dye rhodamine 123 (r123) was used to stain plasmodium yoelii-infected mouse erythrocytes. fluorescence microscopic observations demonstrated that the parasite, but not the matrix of the infected erythrocyte, accumulated the dye. differences in fluorescence intensity could not be found at the various developmental stages of the parasite; however, quantitation of the cell-associated dye revealed an increase in r123 uptake with parasite development. the retention o ... | 1983 | 6198515 |
| serological cross-reaction between high molecular weight proteins synthesized in blood schizonts of plasmodium yoelii, plasmodium chabaudi and plasmodium falciparum. | a 230 000 molecular weight (mw) plasmodium yoelii protein, a 250 000 mw p. chabaudi protein and a 195 000 mw p. falciparum protein, identified using monoclonal antibodies, have similar characteristics, and have been implicated as protective antigens. in this study the serological relationship between these proteins was investigated by western transfer analysis. the monoclonal antibodies specific for each of the high molecular weight proteins did not cross-react with antigens of the other two par ... | 1983 | 6201740 |
| studies of antigens in plasmodium yoelii. i. antigenic differences between parasite lines detected by crossed immunoelectrophoresis. | antigens of three lines of the rodent malaria parasite plasmodium yoelii have been studied using crossed immunoelectrophoresis. p. y. yoelii line a1 is a mild line which is restricted to reticulocytes. p. y. yoelii line ym and p. y. nigeriensis line d1 are virulent infections which multiply in both immature and mature erythrocytes. one antigen, designated py-1, was found to differ in its electrophoretic mobility between the lines, being fast (f) in lines a1 and ym and slow (s) in line d1. antige ... | 1984 | 6206453 |
| studies of antigens in plasmodium yoelii. ii. inheritance and recombination of antigenic characters. | the inheritance of an antigen designated py-1 in the rodent malaria parasite plasmodium yoelii has been investigated. a cross was made between 2 lines differing in the electrophoretic mobility and quantity of py-1 detected by crossed immunoelectrophoresis. in 10 clones isolated from the progeny of the cross the level of py-1 always correlated with the virulence of the infection and it was concluded that these characters were different phenotypic effects of the same gene mutation. the electrophor ... | 1984 | 6206454 |
| genetics of cross-resistance between antifolate drugs in plasmodium yoelii. | | 1982 | 6210768 |
| interactions between the intestinal flagellates giardia muris and spironucleus muris and the blood parasites babesia microti, plasmodium yoelii and plasmodium berghei in mice. | in mice infected with the intestinal flagellates giardia muris or spironucleus muris, together with the blood parasites babesia microti or plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. this decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. the effect on s. muris is more marked than that on g. muris. neither blood p ... | 1982 | 6214756 |
| [system model of plasmodium yoelii--anopheles stephensi for screening tissue schizontocides]. | | 1982 | 6217911 |
| anti-lymphocyte antibodies in lethal mouse malaria. ii. induction of an autoantibody specific suppressor t cell by non-lethal p. yoelii. | the anti-lymphocyte autoantibody response to irradiated lethal plasmodium berghei malaria parasites in normal mice was significantly reduced when recipients were pre-treated with splenic t cells from mice recovered from a non-lethal plasmodium yoelii infection. suppression was specific for the autoantibody and did not affect the antibody response to the parasite. experiments involving sequential p. yoelii-p. berghei infections in situ revealed that recovery from p. berghei was possible when the ... | 1983 | 6225580 |
| changes in the capacity of macrophages and t cells to produce interleukins during murine malaria infection. | interleukin 1 (i1-1) produced by activated macrophages and interleukin 2 (i1-2) released by a subset of t lymphocytes upon antigen or mitogen stimulation are the soluble mediators involved in the mechanism of t-cell activation, proliferation, and differentiation. since these t-cell responses are depressed during malaria infection, the capacity of macrophages to produce i1-1 following lipopolysaccharide (lps) stimulation and that of lymphocytes to release i1-2 upon stimulation with concanavalin a ... | 1984 | 6231107 |
| [a screening method for tissue schizontocides with plasmodium yoelii]. | | 1984 | 6239514 |
| [characterization of plasmodium yoelii antigens by monoclonal antibodies. ii. in vivo assay of the protective effect of monoclonal antibodies]. | | 1984 | 6241048 |
| plasmodium yoelii and plasmodium berghei: isolation of infected erythrocytes from blood by colloidal silica gradient centrifugation. | | 1980 | 6248355 |
| adp-ribosyltransferase in plasmodium (malaria parasites). | the nuclei of plasmodium yoelii nigeriensis contain an enzyme, adp-ribosyltransferase, that will incorporate the adp-ribose moiety of nad+ into acid-insoluble product. the time, ph and temperature optima of this incorporation are 30 min, 8.5 and 25 degrees c respectively. maximum stimulation of the enzyme activity is obtained with 1.0 mm-dithiothreitol or 2.0 mm-2-mercaptoethanol. ca2+ and mg2+ ions at optimum concentrations of 5 mm and 10 mm respectively stimulated the activity of the enzyme by ... | 1983 | 6307262 |
| [observation on factors which affect sporogony of plasmodium yoelii]. | | 1984 | 6331912 |
| enhanced expression of h-2k and h-2d antigens on reticulocytes infected with plasmodium yoelii. | the 17xnl strain of plasmodium yoelii induces a highly effective and permanent t-cell dependent immunity in mice of the cba strain; the lethal variant p. yoelii 17xl and p. berghei (anka) fail to activate an effective immune response in the same host. these differences in immunogenicity are unexplained. we recently observed that in cba/caj mice the intracellular blood stages of p. yoelii 17xnl were almost exclusively within reticulocytes whereas lethal p. yoelii 17xl and p. berghei (anka), at co ... | 1983 | 6339952 |
| endoprotease in plasmodium yoelii nigeriensis. | 1. p. yoelli nigeriensis has an acid endoprotease (cathepsin d) and an endoarylamidase. 2. the acid endoprotease is specific towards haemogloblin. it is found in 2 molecular forms, of molecular weight 100,000 and 50,000. it is inhibited by hematin and pepsatin. 3. in mouse normal red blood cells we find an acid protease having physico-chemical properties similar to those of the enzyme present in p. yoelii nigeriensis extracts, except as regards the phi. 4. in parasite extracts there exists an en ... | 1983 | 6340950 |
| antibody-independent immunity to reinfection malaria in b-cell-deficient mice. | immunity to "reinfection malaria" or "premunition" was studied in b-cell-deficient mice which had previously experienced acute malaria caused by the avirulent plasmodia plasmodium yoelii or p. chabaudi or by the lethal p. vinckei. such mice resisted challenge infection with large numbers of homologous parasites but differed in their capacity to resist challenge with heterologous species. mice immune to p. yoelii resisted infection with p. chabaudi but developed acute-type, albeit nonlethal, infe ... | 1983 | 6350181 |
| heterologous immunity in rodent malaria: comparison of the degree of cross-immunity generated by vaccination with that produced by exposure to live infection. | the degree of heterologous immunity occurring between the different rodent malarias was examined. mice immunized with a killed vaccine consisting of formalin-fixed blood-stage parasites mixed with saponin, were challenged with homologous or heterologous parasites and the degree of protection assessed by monitoring the number of survivors and the duration and severity of parasitaemia. the results indicated that vaccination conferred strong cross-protection between two different plasmodium yoelii ... | 1983 | 6357121 |
| virulent and nonvirulent forms of plasmodium yoelii are not restricted to growth within a single erythrocyte type. | the present studies were designed to investigate whether the erythrocyte preferences displayed by both virulent and nonvirulent forms of plasmodium yoelii were fastidious growth requirements of these parasites. when inoculated into mice depleted of reticulocytes by lethal irradiation (900 rad), virulent parasites, which have been reported to grow predominantly in mature erythrocytes, gave rise to high parasitemias which were equivalent to those seen in unirradiated, normal mice. in addition, vir ... | 1984 | 6368391 |
| role of macrophages in malaria: o2 metabolite production and phagocytosis by splenic macrophages during lethal plasmodium berghei and self-limiting plasmodium yoelii infection in mice. | the role of splenic macrophages in resistance to lethal plasmodium berghei or self-limiting plasmodium yoelii was studied by testing their rate of phagocytosis and their production of o2 metabolites (h2o2 and o2-) upon nonspecific stimulation with zymosan. it was found that, compared with p. berghei, infection of mice with p. yoelii resulted in an earlier appearance and in higher numbers of adherent cells in the spleen. furthermore, the capacity of macrophages to generate o2 metabolites was sign ... | 1984 | 6373617 |
| [growth and decline of parasitemia in trophozoite-induced plasmodium berghei and plasmodium yoelii infection in mice]. | | 1983 | 6380802 |
| early lymphocyte trapping in malaria infections: a particulate antigen mediated phenomenon. | during the course of rodent malaria a marked decrease in the numbers of circulating lymphocytes within the peripheral blood occurred 2-4 days post-infection. monocytes and polymorphs did not show the same degree of decline. for both avirulent plasmodium yoelii and lethal plasmodium berghei infections lymphocyte numbers returned to control levels by day 6-8 post-infection. while these levels were maintained until clearance of p. yoelii infection, a sustained and abnormal increase occurred during ... | 1984 | 6387079 |
| immunoglobulin isotype distribution of malaria-specific antibodies produced during infection with plasmodium chabaudi adami and plasmodium yoelii. | the antibody response of mice to plasmodium chabaudi adami and plasmodium yoelii has been compared using a solid phase isotype-specific radioimmunoassay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. serological cross-reactivity between these parasites was substantial. studies using a radioimmunoassay detecting all classes of malaria-specific antibody demonstrated that during the early part of infection it was not possible to distinguish between homologous and heterologous reacti ... | 1984 | 6467384 |
| [effect of pyronaridine and three other antimalarials on gametocytes and sporogony of plasmodium yoelii]. | | 1984 | 6467538 |
| malarial parasites and tumour cells are killed by the same component of tumour necrosis serum. | tumour necrosis serum (tns), from animals primed with macrophage activating agents and challenged with endotoxin, causes necrosis of some tumours and can kill certain tumour lines in vitro and malarial parasites in vitro and in vivo. we have tested the possibility that the same factor is responsible for killing both tumour cells and malarial parasites. in competitive inhibition experiments, parasitized erythrocytes, but not normal erythrocytes, inhibited the cytotoxicity of tns against a tumour ... | 1984 | 6467675 |
| inhibitory effect of rhodamine 123 on the growth of the rodent malaria parasite, plasmodium yoelii. | the effect of the cationic permeant fluorescent dye, rhodamine 123 (r123), on the in vivo growth of plasmodium yoelii was examined. plasmodium yoelii-infected mouse erythrocytes were incubated in vitro with r123 and injected intravenously into mice. examination of daily parasitemias showed that r123 delayed parasite growth whereas rhodamine 110, a neutral compound, and fluorescein, a negatively charged fluorescent dye, did not. infected erythrocytes treated with r123 were not cleared from the ci ... | 1984 | 6470989 |
| immunoelectrophoretic analysis of erythrocytic stages of plasmodium yoelii and p. chabaudi. | triton x-100 extracts of erythrocytes infected with plasmodium chabaudi and p. yoelii were analysed in crossed immunoelectrophoresis with rabbit antisera. the parasite origin of the antigens detected was assessed by metabolic radiolabelling of the parasites with 35s-methionine. about 12 immunoprecipitates were obtained with both extracts and their homologous antiserum. cross-tests showed that the two parasite strains were very similar antigenically. species-specific antigens could, however, also ... | 1984 | 6506842 |
| in vitro culture of plasmodium yoelii blood stages. | | 1984 | 6511173 |
| the chemotherapy of rodent malaria xxxvi. part iv. the activity of a new 8-aminoquinoline, wr 225,448 against exo-erythrocytic schizonts of plasmodium yoelii yoelii. | light microscope and ultrastructural studies show that wr 225,448, an 8-aminoquinoline related to primaquine, causes substantial damage to developing pre-erythrocytic (ee) schizonts of plasmodium yoelii yoelii in the liver of young rats. in addition to lesions of the mitochondria and nuclear membranes, secretory granules in the parasite fail to reach the surrounding host cell cytoplasm across the parasite membrane. the effective dose of wr 225,448 is much lower than that of primaquine. however, ... | 1984 | 6524991 |
| scanning electron microscopic observations of the oocyst, sporoblast and sporozoite of plasmodium yoelii yoelii. | scanning electron microscopy was used to study the surface characteristics of the oocyst, sporoblast and sporozoite of plasmodium yoelii yoelii. observations were made of the sporogonic stages of 6-12 day infections of the malaria parasite in anopheles stephensi. oocyst and sporoblast development were not synchronous. the surface of the undifferentiated (early stage) oocyst appeared smooth, whereas that of differentiated (late stage) oocysts were rough or wrinkled. the wall of the differentiated ... | 1984 | 6527185 |
| killing of plasmodium yoelii by enzyme-induced products of the oxidative burst. | the murine malaria parasite plasmodium yoelii was killed in vitro when incubated with glucose and glucose oxidase, a system generating hydrogen peroxide, or with xanthine and xanthine oxidase, a system which produces the superoxide anion and subsequently other products of the oxidative burst. catalase blocked the killing in both cases; superoxide dismutase and scavengers of hydroxyl radicals or singlet oxygen were ineffective in the xanthine oxidase system. thus, hydrogen peroxide appears to be ... | 1984 | 6546375 |
| experimentally derived, stable mefloquine resistance in plasmodium yoelii nigeriensis. | | 1983 | 6602406 |
| murine malaria: cellular interactions in the immune response. | the cellular and humoral interactions that contribute to protective immunity in plasmodium yoelii malaria were studied by adoptive transfer of selective cell populations or hyperimmune serum into sublethally irradiated syngeneic c57bl/6 mice. for some experiments pools of mononuclear spleen cells were depleted of t or b lymphocytes and cells that take up silica were inactivated by standard procedures. unfractionated immune spleen cells, but not nonimmune spleen cells, protected recipients from l ... | 1983 | 6606366 |
| histopathology and histochemistry of r.e.s. in infections with plasmodium yoelii nigeriensis. | | 1983 | 6631099 |
| plasmodium yoelii: blood oxygen and brain function in the infected mouse. | the carriage of oxygen by the blood and the in vivo response of the brain were investigated in mice infected with a lethal strain of plasmodium yoelii. all mice with parasitaemia exceeding 70% were severely anaemic (hb 3.5 +/- 1.8 g/dl; mean +/- 1 sd), acidotic (blood ph 7.04 +/- 0.06) and hypoglycaemic (blood glucose 0.6 +/- 0.76 mumol/ml). the oxyhaemoglobin dissociation curve (odc) of blood from heavily infected mice was shifted right as compared to controls, but the increase in p50 was less ... | 1983 | 6641896 |
| characteristics of the protective response of balb/c mice immunized with a purified plasmodium yoelii schizont antigen. | the response of balb/c mice to immunization with a 230,000 mol. wt protective antigen purified from the blood stages of plasmodium yoelii was analysed. the protective response to immunization was adjuvant-dependent, and saponin was found to be the most effective adjuvant tested. the intraperitoneal route was found to be superior to the subcutaneous route for protective immunization. maximal protection was achieved using two immunizations with greater than 12.5 micrograms of antigen plus saponin, ... | 1983 | 6652973 |
| oxidative killing of the intraerythrocytic malaria parasite plasmodium yoelii by activated macrophages. | the capacity of macrophages activated in vivo and in vitro to kill plasmodium yoelii was investigated. macrophages activated by bcg-, con a-, or malaria-induced lymphokines (lk) were cultured with p. yoelii-parasitized erythrocytes (pe). in some experiments, effector and target cells were separated by a 0.45-micron filter. parasite viability was assessed a) in vivo by injection of mice and quantitative detection of parasites by ria or b) in vitro by the incorporation of 3h amino acids into paras ... | 1984 | 6690606 |
| susceptibility of cxb recombinant inbred mice to murine plasmodia. | the genetic control of susceptibility to two species of murine malarial parasites was investigated with recombinant inbred (ri) mouse strains as a model system. initially, the nonlethal plasmodium yoelii 17x strain was cloned by limiting dilution to minimize parasite variability. this cloned p. yoelii was used to infect c57bl and balb/c mice, strains which are the progenitors of the cxb ri strains. since these two strains displayed consistent differences in the kinetics of parasitemia, the seven ... | 1984 | 6698615 |
| blood-stage malaria in biozzi high and low antibody responder mice: the importance of antibody and macrophages in immunity. | mice from biozzi high (h) and low (l) antibody responder lines were infected either with non-lethal plasmodium yoelii 17x, with a lethal variant of the same parasite or with p. chabaudi (non-lethal). h mice recovered from infection with both p. yoelii and its normally lethal variant, whereas l mice died from both. however, l mice showed better initial control of parasitaemia with all three infections. both h and l mice infected with p. chabaudi showed a similar rapid reduction of parasitaemia on ... | 1984 | 6712169 |
| characterization of a high molecular weight protective antigen of plasmodium yoelii. | a 230 000 molecular weight plasmodium yoelii protective antigen was characterized. two monoclonal antibodies against p. yoelii immunoprecipitated the 230 000 mol. wt protein and a number of lower molecular weight polypeptides. these polypeptides were shown by peptide mapping and specific antibody binding to be fragments of the large protein. iodination experiments suggested that the lower molecular weight species may be present on the surface of the merozoite. the protein was found not to be gly ... | 1984 | 6718053 |
| analysis of mrna coding for blood-stage antigens of a rodent malarial parasite, plasmodium yoelii: mrna coding for a possible protective antigen purify as poly a-. | we have analyzed mrna coding for blood-stage antigens of plasmodium yoelii by using cellfree translation of poly a+ and poly a- rna in conjunction with immunoprecipitations. most of the antigens recognized by mouse hyperimmune serum to p. yoelii were coded by poly a+ mrna ranging in size from 15s to 28s. however, certain p. yoelii antigens, notably those with m.w. greater than 150 kilodaltons (kd), were coded by mrna that purified as being poly a-. antigens recognized by a protective monoclonal ... | 1984 | 6725949 |
| ultrastructural localization of protective antigens of plasmodium yoelii merozoites by the use of monoclonal antibodies and ultrathin cryomicrotomy. | the production of two hybridoma cell lines secreting monoclonal antibodies (mab), both of which react specifically with erythrocytic merozoites of plasmodium yoelii in the indirect immunofluorescence assay, has been reported earlier. mab 25.77 was reactive with a localized region within each merozoite, while mab 25.1 appeared to be specific for the plasma membrane of schizonts and merozoites. the parasite antigens recognized by antibodies 25.77 and 25.1 are proteins of 235,000 and 230,000 molecu ... | 1984 | 6731669 |
| inhibition by cyclosporin a of rodent malaria in vivo and human malaria in vitro. | the development and course of normally lethal parasitemias in mice inoculated intraperitoneally with erythrocytic stages of plasmodium yoelii or plasmodium berghei were markedly affected by treatment with the antilymphoid drug cyclosporin a (cs-a). when the first of four daily subcutaneous 25-mg/kg doses of cs-a was given at the time of parasite inoculation, patent infections failed to develop. if begun up to 5 days earlier, this same treatment regimen prolonged the prepatent period, attenuated ... | 1982 | 6752020 |
| differential sensitivity in vivo of lethal and nonlethal malarial parasites to endotoxin-induced serum factor. | sera from mice infected with plasmodium yoelii or plasmodium berghei and given endotoxin contained nonspecific mediators which killed both species of parasite and tumor cells in vitro. the sera resembled tumor necrosis sera obtained from mice given macrophage-activating agents such as propionibacterium acnes (formerly designated corynebacterium acnes) or mycobacterium bovis bcg and then endotoxin. cytotoxicity developed parallel to parasite killing activity and indicated that macrophages were ac ... | 1982 | 6752029 |