Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| [observation on factors which affect sporogony of plasmodium yoelii]. | 1984 | 6331912 | |
| 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 |
| 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 | |
| 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 |
| 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 |
| 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 |
| 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 | |
| cytofluorimetric analysis of dna content in different life stages of plasmodium yoelii. | 1985 | 2423000 | |
| t-cell-mediated immune response in murine malaria: differential effects of antigen-specific lyt t-cell subsets in recovery from plasmodium yoelii infection in normal and t-cell-deficient mice. | for analysis of the role of immune t cells in protective immunity against murine malaria, plasmodium yoelii-immune lyt t-cell subsets were functionally characterized in vitro and in vivo. selected lyt2- and lyt2+ t cells from p. yoelii-immune c57bl/10 mice differed in their capability to proliferate in response to p. yoelii antigen in vitro. only the lyt2- t-cell population produced t-cell growth factor upon restimulation, and none of the selected t-cell subsets produced detectable amounts of ma ... | 1985 | 2857683 |
| re-examination of earlier work on repetitive dna and mosquito infectivity in rodent malaria. | previous results, relating mosquito infectivity to percentage of repetitive dna in the genome of plasmodia, are re-examined in the light of the finding that a parasite line used in the previous studies and classified as plasmodium berghei nk65, was a mixed infection, where the major component appeared to be plasmodium yoelii. this conclusion was reached through cloning and isoenzyme typing of different clones. isoenzyme typing alone is not sufficiently sensitive to reveal contamination amounting ... | 1985 | 2863751 |
| vaccination with a purified blood-stage malaria antigen in mice: correlation of protection with t cell mediated immunity. | a purified 230,000 mol wt protein antigen from the lethal mouse malaria parasite plasmodium yoelii ym which had previously been shown to be highly effective as a vaccine, was tested for its ability to stimulate specific helper t cells and t cells responsible for delayed hypersensitivity. strong stimulation was found in both assays, but larger doses were required for delayed hypersensitivity, correlating well with the requirements for protection. it is suggested that t stimulation may be a requir ... | 1985 | 2933196 |
| oxygen radical release by adherent cell populations during the initial stages of a lethal rodent malarial infection. | a series of experiments was carried out to assess the levels of reactive oxygen intermediates (roi) released by macrophages and monocytes during an acute malarial infection, and to consider the importance of oxidant-induced parasite killing in host protection. adherent cell populations were removed from the peritoneum and spleen of balb/c and b10/d2/n mice between days 0-5 of a plasmodium yoelii nigeriensis infection. these cell populations were quantified, characterized and their roi-releasing ... | 1985 | 3000927 |
| macrophage plasma membrane and secretory properties in murine malaria. effects of plasmodium yoelii blood-stage infection on macrophages in liver, spleen, and blood. | we have studied the effect of infection with the blood-stage of plasmodium yoelii 17x, a nonlethal parasite, on plasma membrane antigens, receptors, and secretory properties of macrophages (m phi) in murine liver, spleen, and blood. mab f4/80 (m phi specific), f7/4 (a marker for immature and immunologically activated m phi, as well as neutrophils), and mac-1, which binds to the type 3 complement receptor, were used to measure the distribution and total content of antigens in situ and to assay su ... | 1986 | 3001215 |
| homologous telomeric sequences are present in different species of the genus plasmodium. | the telomeric sequence cloned from plasmodium berghei (see m. ponzi et al. (1985) embo j. 4, 2991-2995) was tested for species specificity. a telomeric and a subtelomeric fragment of the cloned insert served as separate, labelled probes on pulsed field gradient electrophoretical patterns and on genomic digests from the rodent malarias plasmodium yoelii, plasmodium chabaudi and from the human malaria plasmodium falciparum. results indicate that the subtelomeric fragment, abundantly represented in ... | 1986 | 3024000 |
| changes in oxidative burst capacity during murine malaria and the effect of vaccination. | adherent spleen and liver cells from mice infected with plasmodium yoelii 17x or p. chabaudi as were tested for production of reactive oxygen intermediates to measure their state of activation. phorbol myristate acetate (pma) was used to trigger the respiratory burst and production of superoxide anions was measured by the reduction of nitroblue tetrazolium. spleen cells from mice infected with p. chabaudi showed an early increase in oxidative activity on day 3, and when the oxidative capacity of ... | 1986 | 3026701 |
| antigen-specific, interleukin 2-propagated t lymphocytes confer resistance to a murine malarial parasite, plasmodium chabaudi adami. | to explore cell-mediated immune mechanisms in host defense against malaria, we utilized a murine model system in which antibody-independent mechanisms of immunity are known to play a major role. splenic t lymphocytes obtained from plasmodium chabaudi adami-immune mice were maintained in vitro by using il 2-containing medium and frequent antigenic stimulation. these il 2-propagated t lymphocytes were characterized for their antigen reactivity, surface phenotype, and ability to confer protection t ... | 1986 | 2423609 |
| [intravector anti-plasmodium activity of a pyrethrinoid: deltamethrin]. | in vitro tests, deltamethrin reduced the parasitemic index of plasmodium falciparum on human red blood corpuscles. in vivo tests, at sublethal doses, deltamethrin limited the development of the sporogonic cycle of plasmodium yoelii yoelii in anopheles stephensi. this novel type of antiplasmodic activity involve an intravectorial route and gives an explanation about surprising antimalaria effects observed several months after treatment. | 1986 | 3096513 |
| 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 |
| 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 |
| 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 |
| structure of the gene encoding the circumsporozoite protein of plasmodium yoelii. a rodent model for examining antimalarial sporozoite vaccines. | the gene encoding the circumsporozoite protein (csp) from the rodent malaria parasite, plasmodium yoelii, has been cloned and the nucleotide sequence has been determined. the gene encodes a protein of 367 amino acids as deduced from the nucleotide sequence. this gene is structurally similar to other plasmodium spp. csp genes in that it contains putative hydrophobic signal and anchor sequences at the nh2 and cooh termini, respectively, two small regions (regions i and ii) that are conserved in al ... | 1987 | 3102479 |
| cellular subsets involved in cell-mediated immunity to murine plasmodium yoelii 17x malaria. | cell mediated immunity to nonlethal plasmodium yoelli 17x (py17x-nl) was examined in the cba/caj mouse by adoptive transfer of sensitized t lymphocyte subsets. in intact mice, py17x-nl causes a self-limiting infection with parasitemia levels ranging from 10 to 25% of total red blood cells. upon recovery, mice are refractory to subsequent challenge with the homologous parasite. in t cell-depleted mice, py17x-nl infections are extremely virulent and result in death of the host after parasitemia le ... | 1987 | 3102605 |
| histidine-rich protein in rodent malaria. | mouse red blood cells (rbcs) infected with the malaria parasite plasmodium yoelii nigeriensis were shown to synthesize a histidine-rich protein (his-rp) in vitro. the existence of this protein was demonstrated by comparing fluorograms of infected red blood cells (irbcs) labelled with either [14c]histidine or [14c]leucine. the molecular weight of this his-rp was estimated to be 43,500, which compares well with the values reported for the avian parasite p. lophurae (45,000) and for the human paras ... | 1987 | 3111551 |
| recombinant gamma interferon is a potent adjuvant for a malaria vaccine in mice. | mice were protected against lethal plasmodium yoelii malaria by vaccination with a triton x-100 lysate of whole parasitized erythrocytes. for full effectiveness this vaccine required an adjuvant, and we have found that recombinant gamma-interferon has strong adjuvanticity in this model when given either intraperitoneally or subcutaneously. specific immune responses that were enhanced included antibody, t cell help, and delayed hypersensitivity. | 1987 | 3113784 |
| a rapid method for screening antibodies to plasmodium yoelii liver stages by immunofluorescence. | 1987 | 3325624 | |
| [a simple method for isolating plasmodium yoelii]. | 1987 | 3155375 | |
| activation of liver macrophages in murine malaria is enhanced by vaccination. | during blood-stage infection of mice with a lethal variant of plasmodium yoelii, cells in both spleen and liver became activated to reach a peak at day 5. in mice protected by vaccination, activation was accelerated after infection. the most striking difference observed was in the 10-fold greater yield of infiltrating cells, including macrophages, obtained from the liver just before the mice recovered. their capacity to give an oxidative burst and their cytotoxic activity against tumour cells wa ... | 1987 | 2830070 |
| [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 |
| characterization of plasmodium yoelii monoclonal antibodies directed against stage-specific sporozoite antigens. | a battery of monoclonal antibodies against plasmodium yoelii sporozoites was produced. five of these (nys1 through nys5) were selected for characterization. all five were positive in the indirect immunofluorescent antibody test with p. yoelii sporozoites; however, each showed a different immunofluorescence pattern. although nys1 (immunoglobulin g3 [igg3]), nys2 (igg3), and nys3 (igm) were positive in the circumsporozoite precipitation test, only nys1 and nys2 were able to neutralize sporozoite i ... | 1987 | 2434426 |
| tandemly arranged gene clusters of malarial parasites that are highly conserved and transcribed. | a molecular clone containing a 5.8 kb eco ri fragment was isolated from a genomic library of the rodent malarial parasite plasmodium yoelii. the p. yoelii genome contains about 150 copies of this sequence, making up almost 3% of the dna. these sequences are tandemly arrayed in head-to-tail configurations with the unit length of the repeat being 5.8 kb. several poly(a+) rnas of p. yoelii ranging from 1.6 to 0.3 kb are recognized by the 5.8 kb clone. five additional species of malarial parasites ( ... | 1987 | 3033497 |
| rapid parasite multiplication rate, rather than immunosuppression, causes the death of mice infected with virulent plasmodium yoelii. | protective immunity against a lethal malaria challenge infection was passively transferred to naive recipient mice with spleen cells from donor mice bearing a lethal infection with the virulent ym strain of plasmodium yoelii. successful transfer of protection was contingent upon the elimination of residual, viable parasites from donor spleen cell suspensions prior to the infusion of cells. passive transfer experiments failed to detect suppressor cells in the spleens of lethally infected mice bec ... | 1987 | 2948918 |
| immunization of mice against blood-stage plasmodium yoelii malaria with isoelectrically focused antigens and correlation of immunity with t-cell priming in vivo. | mice were immunized with lethal plasmodium yoelii blood-stage malaria antigens that had been fractionated by isoelectric focusing using a variety of ampholines over the range ph 3 to 10. fractions were tested for their ability to protect against live challenge and to prime for parasite-specific t-cell help. both activities exhibited three major peaks in the ph regions 4.5, 6.5, and 8, the ph 4.5 peak being the most consistently protective. there was a significant correlation between protection a ... | 1988 | 2961703 |
| iron chelators: in vitro inhibitory effect on the liver stage of rodent and human malaria. | the activity of desferrioxamine (desferal) and desferrithiocin (a newly developed oral iron chelator) was evaluated against the liver stage of plasmodium yoelii and p. falciparum in the rodent and the human hepatocyte in vitro culture system. the two iron chelators were found to inhibit the liver schizogony of both the rodent and the human plasmodium species at concentrations achievable in vivo. p. falciparum proved to be more sensitive (ic 95% below 20 micromol/l than p. yoelii (ic 95% 50-100 m ... | 1988 | 3052118 |
| the 3' portion of the gene for a plasmodium yoelii merozoite surface antigen encodes the epitope recognized by a protective monoclonal antibody. | the 230-kda merozoite antigen of the murine malarial parasite plasmodium yoelii provides a potential model system for the development of a protective erythrocytic stage vaccine. to characterize this antigen at the molecular level, isolated p. yoelii 17xl dna was used to construct a genomic library in the expression vector lambda gt11. a monoclonal antibody, mab 302, which passively protected mice against p. yoelii challenge infection, was used to identify a lambda gt11 recombinant clone encoding ... | 1988 | 2448778 |
| molecular clones of alpha-tubulin genes of plasmodium yoelii reveal an unusual feature of the carboxy terminus. | by using a trypanosoma brucei alpha-tubulin cdna probe under reduced stringency hybridization conditions, we have isolated two genomic clones that constitute portions of alpha-tubulin genes of the rodent malarial parasite plasmodium yoelii. p. yoelii has two alpha-tubulin genes, the 3' portions of which were present in the two clones, py alpha t1 and py alpha t2, containing 1.3 kb and 6.6 kb ecori fragments respectively. the 1358 bp py alpha t1 clone was completely sequenced and found to contain ... | 1988 | 2459618 |
| plasmodium yoelii: characterization of a protective idiotype during malarial infection in mice. | we have previously identified and characterized a monoclonal antibody (mcab 302) with potent passive protective activity in mice infected with plasmodium yoelii, a murine malarial parasite which depends on antibodies for resolution. to further study the appearance and regulation of this antibody during infection, we prepared syngeneic monoclonal antibodies specific for idiotopes present on mcab 302. three hybridomas were established which synthesized antibodies that bound only to the homologous ... | 1988 | 2461316 |
| [effect of nitroquine (cl-679) in vitro on incorporation of [3h]hypoxanthine into dna and rna of plasmodium yoelii]. | 1988 | 2461638 | |
| effect of stress conditions on the course of trophozoite-induced plasmodium yoelii nigeriensis in mice recently cured of a previous infection. | the effect of stress conditions on the course of trophozoite-induced plasmodium yoelii nigeriensis in mice recently treated for a previous infection was studied. it was found that when the mice were infected with up to 5943 parasites within 6 days of treating a previous infection, no patent infection was recorded. however, an inoculum of 7924 parasites induced parasitaemia, with a long period of prepatency and a short course of infection before the parasites died out. none of the mice re-infecte ... | 1988 | 2843024 |
| [effects of pyrimethamine on the oocyst formation of plasmodium yoelii yoelii]. | 1988 | 3180361 | |
| [studies on the effective components in protective sera against plasmodium yoelii infections in mice]. | 1988 | 3180365 | |
| changes in the spontaneous flight activity of the mosquito anopheles stephensi by parasitization with the rodent malaria plasmodium yoelii. | an acoustic actograph was used to monitor for 17 days after infection the spontaneous flight activity of the mosquito anopheles stephensi parasitized with the rodent malaria plasmodium yoelii. activity fell to approximately two-thirds of control levels at about day 10 post-infection--when oocysts were reaching maximum size and starting to rupture (mean number of oocysts = 92)--and thereafter remained at this reduced level. the circadian activity pattern was not affected by the parasitism. | 1988 | 3200604 |
| interactions between malaria (plasmodium yoelii) and leishmaniasis (leishmania mexicana amazonensis): effect of concomitant infection on host activity, host body temperature, and vector engorgement success. | 1988 | 3204626 | |
| interactions between plasmodium yoelii and leishmania mexicana amazonensis in leishmania resistant c57b1/6 mice. | we examined the effect of concurrent infection with plasmodium yoelii and leishmania mexicana amazonensis on the course of each disease in leishmania resistant c57bl/6 mice. p. yoelii parasitemia was greatly enhanced when l. m. amazonensis was inoculated 2 days, 3 weeks, or 12 weeks prior to the malaria. lesions due to l. m. amazonensis were enhanced in mice concomitantly infected with p. yoelii compared to mice infected with l. m. amazonensis only. metastatic l. m. amazonensis lesions developed ... | 1988 | 3207174 |
| some studies on acquired immunity to plasmodium chabaudi and plasmodium yoelii in mice. | 1988 | 3217627 |