Publications

protection against malaria by immunization with a plasmodium yoelii circumsporozoite protein nucleic acid vaccine.	nucleic acid vaccines provide an exciting new alternative approach to developing the multiantigen vaccines designed to induce protective antibody and t-cell responses against plasmodium proteins that many experts believe will be required for effective protection against malaria. as a first step in this process, we produced a plasmid dna vaccine that includes the gene encoding the p. yoelii circumsporozoite protein (pycsp). this vaccine induced higher levels of antibodies and cytotoxic t lymphocy ...	1994	7879419
plasmodium yoelii nigeriensis: biological mechanisms of resistance to chloroquine.	the sensitivity to chloroquine according to the degree of synchronicity of plasmodium yoelii nigeriensis, which is considered to be the most resistant of the rodent malaria strains, was studied. the infection was synchronised by means of a percoll-glucose gradient which separates rings and young trophozoites from other stages. the mid-term trophozoite, when it predominated in the blood at the time of treatment, was shown to be as sensitive to chloroquine as plasmodium vinckei petteri. according ...	1994	9140489
attempted isolation of the gene encoding the 21 kd plasmodium berghei ookinete transmission blocking antigen from plasmodium yoelli and plasmodium vivax.	the 21kd ookinete antigen of plasmodium berghei (pbs 21) has been shown to elicit an effective and long lasting transmission blocking immune response in mice. having cloned and sequenced this antigen (paton et al. 1993) the sequence was compared to the genes of the same family previously identified in p. falciparum, p. gallinaceum (kaslow et al. 1989) and p. reichenowi (lal et al. 1990). four conserved areas were identified in this comparison, to which degenerate oligonucleotides were designed. ...	1994	7565129
cloning and structural analysis of the gene for camp-dependent protein kinase catalytic subunit from plasmodium yoelii.	we isolated the gene encoding the camp-dependent protein kinase catalytic subunit (capk[c]) from plasmodium yoelii by screening a genomic library for the dna fragment as produced by the polymerase chain reaction. the deduced protein of 341 amino acids conserves residues that are important for the function of serine/threonine protein kinases and shows the highest homology to capk[c]s of other organisms. however, p. yoelii capk[c] has 8 residues, which are perfectly conserved in capk[c]s of other ...	1995	7578264
humoral response to a carboxyl-terminal region of the merozoite surface protein-1 plays a predominant role in controlling blood-stage infection in rodent malaria.	the developmental stages of malaria parasites that infect e are responsible for the morbidity and mortality associated with this disease. one of the leading candidates for a blood-stage vaccine against malaria is a surface protein of merozoites, the infectious stages for e, designated merozoite surface protein-1 (msp-1). the rodent malarial parasite plasmodium yoelii yoelii (py) has provided a model system for the study of this ag, and previous studies from our laboratory had demonstrated that t ...	1995	7602100
antimalarial effects of c18 fatty acids on plasmodium falciparum in culture and on plasmodium vinckei petteri and plasmodium yoelii nigeriensis in vivo.	following the demonstration of the antimalarial effect of the long chain saturated alcohol n-hentriacontanol ((ch2)29ch2oh), isolated from the bolivian endemic solanaceous plant cuatresia sp., we have tested the effect of the c18 fatty acids oleic, elaidic, linoleic, and linoleic on malaria parasites. these fatty acids inhibited the parasitemic development in mice infected with plasmodium vinckei petteri or with plasmodium yoelii nigeriensis in a 4-day suppressive test. to gain a deeper discernm ...	1995	7628573
induction of protective polyclonal antibodies by immunization with plasmodium yoelii circumsporozoite protein multiple antigen peptide vaccine.		1995	7636221
complexity of the cytokine and antibody response elicited by immunizing mice with plasmodium yoelii circumsporozoite protein plasmid dna.	the number, type, and location of cytokine- and ab-secreting cells activated in mice immunized and boosted with plasmid dna encoding the circumsporozoite protein of the malarial parasite plasmodium yoelii (pycsp) were monitored. the initial humoral response was localized to the draining lymph nodes and was characterized by production of igg1 anti-pycsp abs and the th2 cytokine il-4. in contrast, the secondary response was dominated by ifn-gamma production (a th1 cytokine) and the secretion of ig ...	1995	7636255
dietary fish oils and long-term malaria protection in mice.	previous studies indicate a suppressive influence of fish oils on rodent malaria. the present work was carried out to study (i) the dose-effect relation between dietary fish oils and lethality of primary malaria infection in mice; (ii) the modifying influence of vitamin e; and (iii) the effect of previous fish oil feeding on parasitemia and lethality of a rechallenge infection. for two or four weeks, groups of weanling male mice were fed a standard laboratory diet or one of eight purified diets ...	1995	7637564
multiple genes code for high-molecular-mass rhoptry proteins of plasmodium yoelii.	we have examined the number of genes coding for a group of high-molecular-mass rhoptry protein(s) in the malaria parasite plasmodium yoelii, and studied variation in the gene family within the parasite's genome. a region of the genes was amplified using oligonucleotides based on conserved dna sequences and the products cloned. the sequences could be divided into 7 groups by restriction-fragment-length polymorphism. further variation was detected by sequence analysis; 11 different sequences were ...	1995	7637695
the chemotherapy of rodent malaria. lii. response of plasmodium yoelii ssp. ns to mefloquine and its enantiomers.	a comparison was made between the blood schizontocidal action in mice of racemic mefloquine hydrochloride and the free bases of its (+)- and (-)-enantiomers (ro 13-7224 and ro 13-7225) against chloroquine-resistant plasmodium yoelii ssp. ns. the racemic hydrochloride was two to three times as active against this parasite in mice as either of the enantiomer free bases, which were of similar activity to each other. under drug selection pressure, the parasites acquired resistance in approximately t ...	1995	7495359
the combined epidermal growth factor-like modules of plasmodium yoelii merozoite surface protein-1 are required for a protective immune response to the parasite.	we have reported previously that immunization with a bacterial recombinant protein containing the two epidermal growth factor (egf)-like modules of plasmodium yoelii merozoite surface protein-1 (msp-1) protected mice against challenge with this malaria parasite. bacterial plasmids containing sequences coding for the individual modules fused to glutathione s-transferase (gst) have now been made. the fusion protein containing the combined egf-like modules was recognized by anti-parasite antibodies ...	1995	7501423
immunization of albino mice using chloroquine attenuated plasmodium yoelli nigeriensis.	in an attempt to induce chloroquine resistance in plasmodium yoelii nigeriensis by the method of drug pressure, it was found that the mice continued to be infected until the fourth passage when they became refractory or immune to the infection. when the immune mice were challenged at four weekly intervals, they remained refractory to the infection until week 12 when one of them became infected. however, by the sixteenth week, the rest of the mice became susceptible to the infection. four of the ...	1995	8904069
blood-stage malaria infection in diabetic mice.	infection of mice with blood-stage plasmodium yoelii and p. chabaudi malaria induced hypoglycaemia in normal mice and normalized the hyperglycaemia of mice made moderately diabetic with streptozotocin (stz). injection of parasite supernatants induced hypoglycaemia accompanied by hyperinsulinaemia in normal mice, and in stz-diabetic mice induced a profound drop in blood glucose and restored insulin secretion; however, severely diabetic mice (two injections of stz) remained hyperglycaemic with no ...	1995	7882567
murine complement reduces infectivity of plasmodium yoelii to mosquitoes.	the alternative pathway of complement in the mouse serum significantly reduced, but did not eliminate, the infectivity of plasmodium yoelii to anopheles stephensi. the reduction of the infectivity is mainly due to the inability of the zygote to transform into the ookinete in the mosquito midgut.	1995	7642309
induction of long-lasting immunity to plasmodium yoelii malaria with whole blood-stage antigens and copolymer adjuvants.	we previously reported that protection of mice from nonlethal plasmodium yoelii malaria by immunization with whole killed blood-stage parasites was dependent on the adjuvant and that adjuvants influenced both the specificity and isotype of ab. additional studies with the most effective formulations were undertaken to better define the protective responses and 100% protection from lethal p. yoelii malaria was produced by three immunizations with ag in copolymer p1004 and detoxified ralps as adjuv ...	1995	7836760
plasmodium yoelii in mice: differential induction of cytokine gene expression during hyporesponsiveness induction and restimulation.	acute plasmodium yoelii murine malaria is associated with a marked depression of splenic t cell responses. the present study was undertaken to address the question if a defect in t cell proliferation results from a relative increase of a non-t cell population in the spleen or real biological changes occurring in t cells of the spleen after infection. when animals were acutely infected, the splenic cells responded poorly to cross-linked anti-cd3 mab, con a, and pwm stimulation. at this stage, a v ...	1995	7842488
induction of protective polyclonal antibodies by immunization with a plasmodium yoelii circumsporozoite protein multiple antigen peptide vaccine.	monoclonal abs against the repeat region of the circumsporozoite protein (csp) completely protect mice against plasmodium yoelii (py), but synthetic peptide and recombinant protein vaccines designed to produce only abs to the pycsp repeat region have never been reported to consistently provide protection. this lack of protection in the rodent model system has predicted the poor protection achieved in humans after immunization with synthetic peptide and recombinant protein p. falciparum csp vacci ...	1995	7876549
plasmodium yoelii yoelii 17xl msp-1: fine-specificity mapping of a discontinuous, disulfide-dependent epitope recognized by a protective monoclonal antibody using expression pcr (e-pcr).		1995	7534725
identification of a nonameric h-2kk-restricted cd8+ cytotoxic t lymphocyte epitope on the plasmodium falciparum circumsporozoite protein.	class i-restricted cd8+ cytotoxic t lymphocytes (ctl) against the circumsporozoite protein (csp) protect mice against the rodent malaria parasite, plasmodium yoelii, and vaccines designed to produce protective ctl against the p. falciparum csp (pfcsp) are under development. humans and b10.br (h-2k) mice have been shown to have cd8+ ctl activity against a 23-amino-acid region of the pfcsp (residues 368 to 390 from the pfcsp 7g8 sequence) that is too long to bind directly to class i major histocom ...	1995	7537251
development of antimalaria immunity in mice lacking ifn-gamma receptor.	ifn-gamma receptor deficient (ifn-gamma r-/-) mice, immunized with different developmental stages of malaria parasites, were used to define the mechanisms of protection against the various stages of this infection. ifn-gamma r-/- mice failed to develop protective immunity against plasmodium yoelii sporozoites or liver stages, upon immunization with a single dose of irradiated sporozoites, whereas in immunized wild-type mice, parasite development was strongly inhibited. immunized wild-type mice e ...	1995	7537305
hla-a2-restricted cytotoxic t lymphocyte responses to multiple plasmodium falciparum sporozoite surface protein 2 epitopes in sporozoite-immunized volunteers.	cd8+ ctl specific for the plasmodium yoelii sporozoite surface protein 2 (pyssp2) protect mice against malaria. for this reason, vaccines designed to induce ctl against p. falciparum ssp2 (pfssp2) are under development. optimal development of pfssp2 as a component of human malaria vaccines requires characterization of hla class i-restricted ctl against this ag. for this purpose, pbmc from four hla-a2+ human volunteers immunized with p. falciparum irradiated sporozoites were stimulated with a rec ...	1995	7541824
[a preliminary study on the inhibitory action of target-primaqine on the exoerythrocytic forms of plasmodium yoelii yoelii].	target-primaquine (tpq)--the primaquine entrapped by galactosylneoglycoalbumin (g-nga), was given intravenously (iv) to wistar rats 2 h after sporozoite inoculation. the sporozoite viability (spv) of tpq 20 mg/kg group was revealed to be 1.2% 42 h after inoculation, which showed a decline of about 6% as compared to the control; besides, degeneration or retardation of development was present in 90% of eef. in tpq 10 mg/kg and pq 20 mg/kg groups, the spv were 2.8% and 5.0%, respectively, showing d ...	1995	7554159
immunization with the malaria heat shock like protein hsp70-1 enhances transmission to the mosquito.	mosquitoes fed on mice infected with plasmodium yoelii after an immunization with the i72 recombinant form of the heat shock protein hsp70-1 developed significantly more oocysts than mosquitoes fed on controls. this effect was due to a marked increase in the relative numbers of gametocytes during the early stages of infection. a comparison of blood-induced and sporozoite-initiated infection showed that these gametocytes were derived from merozoites released from the liver. the stimulus for incre ...	1995	7718511
plasmodium yoelii: 17-kda hepatic and erythrocytic stage protein is the target of an inhibitory monoclonal antibody.	infected hepatocytes are important targets for malaria vaccines. to identify plasmodium yoelii proteins expressed in infected hepatocytes, we immunized balb/c byj mice with p. yoelii liver stage schizonts and produced a panel of monoclonal antibodies (mabs). an igg1 mab, navy yoelii liver stage 3 (nyls3), had the strongest reactivity against liver stage parasites and was selected for further characterization. the mab does not recognize p. yoelii sporozoites, but recognizes liver stage parasites ...	1995	7729477
partial protection against malaria by immunization with leishmania enriettii expressing the plasmodium yoelii circumsporozoite protein.	since infection with leishmania species induces cd4+ and cd8+ anti-leishmania t cells, we assessed protection against malaria by immunization with leishmania enriettii transfected with the gene encoding the plasmodium yoelii circumsporozoite protein (pycsp). the recombinant plasmid appeared to be a circular episome in the host cells. reverse transcription pcr showed that the pycsp was trans-spliced by the addition of the 39-bp spliced leader of l. enriettii at its 5' end. the transfectant expres ...	1995	7770079
malaria-induced reduction of fecundity during the first gonotrophic cycle of anopheles stephensi mosquitoes.	anopheles stephensi mosquitoes which had fed upon mice infected with plasmodium yoelii nigeriensis malaria parasites produced significantly fewer eggs than mosquitoes fed on an uninfected mouse. fecundity reduction was more pronounced when the bloodmeal contained malaria gametocytes and the mosquitoes developed oocysts. egg production and haematin excretion were correlated for uninfected bloodfed mosquitoes; the presence of p.y.nigeriensis in the blood affected this relationship. reduced fecundi ...	1995	7787226
effects of iron deficiency on the hepatic development of plasmodium yoelii.	iron deficiency through an iron-deficient diet and through an inactivation of hepatic xanthine dehydrogenase (xd) was shown to modulate plasmodium yoelii sporozoite development in hepatocytes. when mice that are on iron-deficient diet were challenged with sporozoites, enhancement of hepatic stage development was observed, resulting in the earlier appearance of blood parasites. in contrast, inhibition of parasite hepatic development was noticed when iron deficiency was the result of hepatic xd in ...	1995	8745736
postprandial lymphatic flux and malaria.	24 hours after an intra-peritoneal inoculation of frozen blood infected with plasmodium yoelii nigeriensis, the malarial infection is non detectable in most starved mice while it is patent in mice fed 2 hours before the inoculation. it is assumed that the post feeding lymphatic flow brings to the blood the latent merozoites.	1995	8745741
plasmodium vinckei vinckei and p. yoelii nigeriensis: pattern of gametocyte production and development.	the morphological evolution and the periodicity of the gametocytes of two rodent malaria species were studied in the white mouse. experiments with plasmodium vinckei vinckei, a highly synchronous species, showed that the production of the sexual stages was periodic and was set by the specific rhythm of the asexual stages, i.e. the time of inoculation and the duration of the cycle in the blood. the duration of gametocytogenesis from merozoite to stage 0 was approximately 30 hours, and from stage ...	1995	8532362
plasmodium yoelii: expression of circumsporozoite protein and sporozoite surface protein 2 by sporozoites in culture.		1995	8543002
noninfectious sporozoites in the salivary glands of a minimally susceptible anopheline mosquito.	in studies to evaluate vector-malaria parasite relationships, we have found that anopheles albimanus is minimally susceptible to the rodent malaria parasite plasmodium yoelii. normally, less than 10% of a. albimanus develop oocyst infections compared to 80-100% for anopheles stephensi and anopheles freeborni mosquitoes. although sporozoites produced in a. albimanus invade the salivary glands, they are not infectious to balb/c or icr mice. in 11 experiments with sporozoites from a. albimanus, int ...	1995	8544063
protective immunity against malaria: cellular changes in the liver vary according to the method of immunization.	characterization of cells present in the extravascular compartment of murine liver was performed after different immunization procedures against the malaria parasite plasmodium yoelii. mice were immunized with live or irradiated sporozoites or with parasitized erythrocytes. whatever the immunization protocol used, the mice were protected against a sporozoite challenge but each immunization procedure induced a specific profile of cell types. immunization with irradiated sporozoite induce a signif ...	1995	8552416
plasmodium yoelii nigeriensis: the effect of high and low intensity of infection upon the egg production and bloodmeal size of anopheles stephensi during three gonotrophic cycles.	anopheles stephensi mosquitoes showed a reduction in fecundity over 3 successive gonotrophic cycles, after becoming infected with plasmodium yoelii nigeriensis. this effect could be observed at high oocyst burdens (> 75) or at low oocyst burdens (mean of 4.36). mean bloodmeal size of the infected mosquitoes was significantly reduced only when feeding upon a mouse with a high gametocytaemia and the conversion of the bloodmeal into eggs by the infected mosquitoes was disrupted. patterns of infecte ...	1995	8559587
dominance of conserved b-cell epitopes of the plasmodium falciparum merozoite surface protein, msp1, in blood-stage infections of naive aotus monkeys.	we have shown that conserved b epitopes were immunodominant in animals hyperimmunized with parasite-purified or recombinant merozoite surface protein msp1 of plasmodium falciparum. cross-priming studies also suggested that a conserved t-helper epitope(s) is efficient in inducing the anti-msp1 antibody response. in this study, we determined whether a similar profile of immune responses was induced during live p. falciparum infections. naive aotus monkeys were infected by blood-stage challenge wit ...	1996	8613353
plasmodium yoelii: the role of the individual epidermal growth factor-like domains of the merozoite surface protein-1 in protection from malaria.	the merozoite surface protein-1 (msp-1) is a leading candidate for a vaccine targeted at the erythrocytic stages of plasmodial parasite development. recently, there has been increasing interest in this polypeptide, particularly in the carboxyl-terminal egf-like domains. we have previously shown that this region from plasmodium yoelii, when expressed in native configuration, could immunize mice against an otherwise lethal challenge infection. in this model system, protection appears to be predomi ...	1996	8617331
identification and characterization of the protective hepatocyte erythrocyte protein 17 kda gene of plasmodium yoelii, homolog of plasmodium falciparum exported protein 1.	we recently reported the discovery of a 17-kda plasmodium yoelii protein expressed in infected hepatocytes and erythrocytes, p. yoelii hepatocyte erythrocyte protein 17 (pyhep17), and have demonstrated that this protein is a target of protective antibodies and t cells. here, we report the identification and characterization of the gene encoding this protein and reveal that it is composed of two exons. immunization of mice with pyhep17 plasmid dna induces antibodies, cytotoxic t lymphocytes, and ...	1996	8663412
circumventing genetic restriction of protection against malaria with multigene dna immunization: cd8+ cell-, interferon gamma-, and nitric oxide-dependent immunity.	despite efforts to develop vaccines that protect against malaria by inducing cd8+ t cells that kill infected hepatocytes, no subunit vaccine has been shown to circumvent the genetic restriction inherent in this approach, and little is known about the interaction of subunit vaccine-induced immune effectors and infected hepatocytes. we now report that immunization with plasmid dna encoding the plasmodium yoelii circumsporozoite protein protected one of five strains of mice against malaria (h-2d, 7 ...	1996	8666931
reversal of hypoglycaemia in murine malaria by drugs that inhibit insulin secretion.	we have investigated the metabolic disturbances in 2 murine models of blood-stage malaria, plasmodium chabaudi and plasmodium yoelii. blood glucose, plasma insulin and parasitaemia were measured in normal and infected mice before and after treatment with diazoxide, adrenaline, sandostatin and quinine. severe hypoglycaemia and marked hyperinsulinaemia developed during both infections. a single injection of diazoxide (25 mg/kg i.p.) or adrenaline (0.03 mg s.c.) lowered insulin concentrations in no ...	1996	8684825
influence of adjuvants on protection induced by a recombinant fusion protein against malarial infection.	previously, we described a protective immune response induced by the carboxyl-terminal region of the merozoite surface protein-1 (msp-1) from the rodent malarial parasite plasmodium yoelii yoelii 17xl, expressed as a fusion protein and designated glutathione s-transferase (gst)-pyc2. we also demonstrated that the humoral response induced by gst-pyc2 was the primary mechanism by which immunized animals controlled their blood-stage infections. we have now examined the influence of several adjuvant ...	1996	8698485
production of interleukin 10 during malaria caused by lethal and nonlethal variants of plasmodium yoelii yoelii.	we investigated the induction of t-helper cell subsets during the course of lethal or nonlethal bloodstage plasmodium yoelii 17x infection in c57bl/6 mice, which are relatively susceptible to these intraerythrocytic parasites. c57bl/6 mice infected with the nonlethal variant (pynl) showed a moderate level of parasitemia and resolution of primary acute infection by week 4. mice infected with the lethal variant (pyl) developed fulminating parasitemia and ultimately died. t-helper subset function w ...	1996	8738275
cytokines and antibody subclass associated with protective immunity against blood-stage malaria in mice vaccinated with the c terminus of merozoite surface protein 1 plus a novel adjuvant.	a blood-stage malaria antigen comprising the c terminus of merozoite surface protein 1 fused to glutathione s-transferase, combined with an adjuvant formulation containing squalane, tween 80, and pluronic l121 (af), administered subcutaneously protected mice against death from a lethal plasmodium yoelii infection. the protection induced by this antigen-adjuvant combination was compared with that induced by the antigen plus saponin in terms of survival from the lethal infection and clearance of p ...	1996	8751895
genetic regulation of protective immune response in congenic strains of mice vaccinated with a subunit malaria vaccine.	the c-terminal 19-kda, epidermal growth factor-like region of the merozoite surface protein 1 (msp1) has been used as a vaccine to induce protective immunity to plasmodium yoelii in mice and to plasmodium falciparum in monkeys. to analyze the mechanisms and genetic regulation of this msp1 vaccine-induced protection, we studied the immunologic correlates of protection in h-2 recombinant and congenic mouse strains on the b10 background. multiple h-2-linked loci were found to contribute, each with ...	1996	8757623
studies on ammonia-metabolizing enzymes during plasmodium yoelii infection and pyrimethamine treatment in mice.	blood ammonia content and enzymes involved in ammonia metabolism, namely glutamine synthetase (gs), glutamate dehydrogenase (gdh), monoamine oxidase (mao), alanine amino-transferase (alt) and aspartate aminotransferase (ast), were studied in plasmodium yoelii-infected drug-treated mice tissues. the ammonia content in blood increased with the rise of parasitaemia. hepatic gs, gdh and mao showed a marked decrease in enzyme activity during parasitic infection. in contrast, cerebral gs and mao showe ...	1996	8773535
the large difference in infectivity for mice of plasmodium berghei and plasmodium yoelii sporozoites cannot be correlated with their ability to enter into hepatocytes.	sporozoites of p. yoelii nigeriensis are 50-100-times more infective to mice than the strain nk65 of p. berghei. to study the mechanisms involved in this striking difference in the infectivity of these closely related species of malaria parasites, we have developed a quantitative pcr targeted to parasite-specific ribosomal rna. using this method, we detect rna from a single sporozoite, and exo-erythorcytic forms of rna in the livers of mice injected with 200 sporozoites. we find that 20 h after ...	1996	8784767
sequence analysis of the apical membrane antigen-1 genes (ama-1) of plasmodium yoelii yoelii and plasmodium berghei.		1996	8813699
stable expression and secretion of the b-cell epitope of rodent malaria from mycobacterium bovis bcg and induction of long-lasting humoral response in mouse.	the live bacterial vaccine mycobacterium bovis bcg (bcg) is a vehicle worth noticing for various protective antigens. the gene encoding the b-cell epitope of the oligopeptide repeating in the circumsporozoite protein (c.s. protein) of the rodent malaria parasite, plasmodium yoelii, was inserted into the plasmid vector under the control of an expression cassette carrying the promoter and signal sequence of the a antigen derived from mycobacterium kansasii (k-a). the b-cell epitope was successfull ...	1996	8821650
a novel 70-kda triton x-114-soluble antigen of plasmodium falciparum that contains interspecies-conserved epitopes.	in order to identify novel conserved integral membrane and other membrane-associated proteins of plasmodium falciparum, lambda gt11-p. falciparum dna library phages were immunoscreened with convalescent-phase mouse sera and rabbit antiserum against triton x-114-soluble proteins of p. falciparum. one recombinant phage clone, l857, reacted with both of the antibody probes. insert dna (857 bp long) in l857 was 69% da+dt rich and hybridized to a fragment of 1800 bp from mung bean nuclease-digested p ...	1996	8823249
lactate dehydrogenase as a marker of plasmodium infection in malaria vector anopheles.	lactate dehydrogenase (ldh) electrophoresis showed the presence of plasmodium yoelii yoelii in anopheles stephensi and an. gambiae. the ldh appeared as an additional band (pldh) whose activity was more intense with 3-acetyl pyridine adenine dinucleotide as coenzyme than with beta nicotin-amide adenine dinucleotide. several allelic forms occurred both in the vector and the host. the isoelectric point of ldh, similar in the vector and host, differed from those of ldh from mosquito and mouse. the p ...	1996	8827592
iron overload increases hepatic development of plasmodium yoelii in mice.	iron overload in balb/c mice by treatment with ferric ammonium citrate promotes the hepatic development of plasmodium yoelii in vivo and in vitro. this was the result of increased penetration of the parasite into hepatocytes since no effect was observed on parasite transformation or maturation. these results could explain why in endemic regions iron supplementation led, in certain studies, to an increase in clinical episodes of malaria and in the prevalence of malaria infection.	1996	8851855
protection against malaria by plasmodium yoelii sporozoite surface protein 2 linear peptide induction of cd4+ t cell- and ifn-gamma-dependent elimination of infected hepatocytes.	plasmodium falciparum sporozoite surface protein 2 (ssp2), also known as trap, is included in experimental human malaria vaccines because plasmodium yoelii ssp2 is the target of protective cd8+ ctl that eliminate p. yoelii-infected hepatocytes in mice. we now report that immunization with a synthetic branched-chain peptide including four copies of a pyssp2 sequence, npneps, and two tetanus toxin t helper epitopes in the adjuvant titermax, or with an 18 amino acid peptide (npneps)3 in the adjuvan ...	1996	8892640
genes for chemokines mumig and crg-2 are induced in protozoan and viral infections in response to ifn-gamma with patterns of tissue expression that suggest nonredundant roles in vivo.	mumig and crg-2 are ifn-inducible murine chemokines whose human homologues, humig and ip-10, respectively, share activity in vitro as t cell chemoattractants. we analyzed the expression of the genes mumig, crg-2, and ifn-gamma during experimental infections with plasmodium yoelii, toxoplasma gondii, and vaccinia virus. mumig, crg-2, and ifn-gamma were induced in multiple organs. during the acute phase of each infection as well as after i.p. injection of rifn-gamma, levels of mumig mrna in the li ...	1996	8906829
a high molecular mass plasmodium yoelii rhoptry protein binds to erythrocytes.		1996	8920020
comparison of two members of a multigene family coding for high-molecular mass rhoptry proteins of plasmodium yoelii.		1996	8920022
plasmodium yoelii: peptide immunization induces protective cd4+ t cells against a previously unrecognized cryptic epitope of the circumsporozoite protein.	in this study we characterized the cd4+ t cell response directed against two distinct epitopes located in the circumsporozoite (cs) protein of plasmodium yoelii. the immunization of mice with p. yoelii sporozoites induced cd4+ t cells which were mostly directed against one of these peptides, py-1, previously reported to contain a cd4+ epitope. the cd4+ t cells directed against this immunodominant epitope were mostly of the th-1 type. another newly identified peptide, as44, induced a specific cd4 ...	1996	8932772
in vivo treatment with interleukin 2 reduces parasitemia and restores ifn-gamma gene expression and t-cell proliferation during acute murine malaria.	in this study, we describe the functional alterations in the host immune system that occur following acute infection with plasmodium yoelii. further, we have addressed the question whether the transient condition of altered immune responsiveness can be restored by a cytokine therapy. the lymphoproliferative response towards concanavalin a (con a) or to cross-linked anti-cd3 mab was significantly diminished in acutely infected mice compared to immune and normal animals. this condition was associa ...	1996	8949394
dna vaccines against malaria: immunogenicity and protection in a rodent model.	since the first demonstration of the technology a few years ago, dna vaccines have emerged as a promising method of vaccination. in a variety of experimental systems, dna vaccines have been shown not only to induce potent immune responses, but also to offer many advantages in terms of ease of construction, testing, and production. in this article we summarize the progress achieved in development of dna vaccines that can protect mice from infection by the rodent malaria parasite plasmodium yoelii ...	1996	8961142
both epidermal growth factor-like domains of the merozoite surface protein-1 from plasmodium yoelii are required for protection from malaria.		1996	8993373
induction of chloroquine resistance in plasmodium yoelii nigeriensis.	chloroquine resistance was induced in plasmodium yoelii nigeriensis by the method of drug pressure. twenty five albino mice were used at each passage and each of them was inoculated intra-peritoneally with approximately 10(5) erythrocytes infected with the parasite. the first fifteen mice divided into three groups of five mice each were treated with different sub-curative doses of chloroquine which usually cleared the infection for a few days before recrudescence. inocula for passages to the nex ...	1996	8997840
efficacy of cymbopogon giganteus and enantia chrantha against chloroquine resistant plasmodium yoelii nigeriensis.	the antimalarial activity of boiled water extracts of two medicinal plants (cymbopogon giganteus and enantia chlorantha) against chloroquine resistant plasmodium yoelii nigeriensis in albino mice was assessed. twenty-five mice were used for each extract. each mouse was inoculated with approximately 10(5) erythrocytes infected with chloroquine-resistant p.y. nigeriensis. at five to seven percent parasitaemia, the mice were randomly divided into five groups of five mice each. the first four groups ...	1996	8997841
protective efficacy against malaria of a combination sporozoite and erythrocytic stage vaccine.	most malariologists believe that optimal malaria vaccines will induce protective immune responses against different stages of the parasite's life cycle. a multiple antigen peptide (map) vaccine based on the plasmodium yoelii circumsporozoite protein (pycsp) protects mice against sporozoite challenge by inducing antibodies that prevent sporozoites from invading hepatocytes. a purified recombinant protein vaccine based on the p. yoelii merozoite surface protein-1 (pymsp-1) protects mice against ch ...	1996	9024983
synchronized plasmodium yoelii yoelii: pattern of gametocyte production, sequestration and infectivity.	the chronobiology of the gametocytes of p. yoelii was studied in percoll-glucose synchronized infection in the mouse. the gametocyte developmental cycle consisted of 4 successive stages: stage 0 maturation took 27 hours from merozoite invasion, stage 0 to stage 1 lasted 6 hours, stage i to stage ii and stage ii to stage iii lasted 3 hours each. stage 0 gametocytes were found to sequester in small peripheral capillaries, and the number of oocysts in mosquitoes was related to the number of stage 0 ...	1996	9257348
[inhibition of the development of plasmodium yoelii in exoerythrocytic stage in rodents (rats) with chrysanthemum morifolium].		1996	9389080
antimalaric effect of an alcoholic extract of artemisia ludoviciana mexicana in a rodent malaria model.	chloroquine resistance of plasmodium falciparum first and of p. vivax more recently, stimulated the search for new antimalarics. chinese investigators have introduced new compounds obtained from extracts of artemisia annua which possess an antimalaric active principle different from those of the drugs in use. in mexico eight species of artemisia have been described and among them just a. ludoviciana has been empirically used in the treatment of intermittent fever. to know whether mexican artemis ...	1997	9419840
plasmodium yoelii sporozoite infectivity varies as a function of sporozoite loads in anopheles stephensi mosquitoes.	mechanisms by which plasmodium sporozoites survive and maintain their infectivity within the salivary glands of mosquitoes are unknown. in this study we establish a relationship between the number of sporozoites present in the salivary glands of individual mosquitoes (sporozoite load) and sporozoite infectiousness (or "quality") as measured by infections in balb/c or icr mice. when plasmodium yoelii-infected anopheles stephensi mosquitoes were each allowed to feed on a single mouse, we noted tha ...	1997	9267407
sporozoites of plasmodium yoelii infect mice with targeted deletions in icam-1 and icam-2 or complement components c3 and c4.		1997	9274888
the effects of infection with plasmodium yoelii nigeriensis on the reproductive fitness of anopheles stephensi.	infection with the rodent malarial parasite plasmodium yoelii nigeriensis caused a significant reduction in the reproductive fitness (number of eggs produced and proportion of eggs hatched) of two different generations of anopheles stephensi. overall fertility (number of larvae produced) was reduced by 38.3% in the generation containing smaller mosquitoes (with a wing length of 3.2 +/- 0.1 mm) with relatively larger parasite burdens, and by 48.81% in the generation containing larger mosquitoes ( ...	1997	9290843
the chemotherapy of rodent malaria. lv. interactions between pyronaridine and artemisinin.	two interactions of two potent blood schizontocides, pyronaridine and artemisinin, were assessed in mice infected with chloroquine-resistant plasmodium yoelii ssp. ns or one of two lines derived from it, namely art, which is resistant to artemisinin and spn, which is resistant to pyronaridine. while the drug combination proved to be only additive in its action against p. yoelii ssp. ns, a marked potentiation between the two compounds was observed against the art and spn lines. the implications o ...	1997	9307655
complete protective immunity induced in mice by immunization with the 19-kilodalton carboxyl-terminal fragment of the merozoite surface protein-1 (msp1[19]) of plasmodium yoelii expressed in saccharomyces cerevisiae: correlation of protection with antigen-specific antibody titer, but not with effector cd4+ t cells.	the 19-kda carboxyl-terminal fragment of the merozoite surface protein-1 (msp1) is a leading malaria vaccine candidate but is unable to induce immunity in all monkeys or all strains of mice. the mechanism of immunity is unclear, although data show that cell-mediated immunity plays a critical role following immunization with the larger mature msp1 protein. we optimized a vaccine protocol using the msp1(19) fragment of plasmodium yoelii expressed in saccharomyces cerevisiae, such that following ex ...	1997	9317139
induction of protective ctl responses against the plasmodium yoelii circumsporozoite protein by immunization with peptides.	to determine the optimum combination, concentration, and formulation of synthetic peptides and adjuvants to induce protective ctl responses against the plasmodium yoelii circumsporozoite protein (pycsp), balb/c mice were immunized with linear and multiple antigen peptides (map) including pycsp ctl and th epitopes in montanide's isa51, lipofectin, and lipofectamine. an h-2k(d)-restricted pycsp ctl epitope, syvpsaeqi (amino acids (aa) 280-288), recognized by protective ctl clones, was included in ...	1997	9317141
bacterial expression and purification of recombinant plasmodium yoelii circumsporozoite protein.	we report the expression and purification of recombinant rodent malarial plasmodium yoelii circumsporozoite surface protein (pycsp) in escherichia coli. to facilitate purification of the recombinant protein, the pycsp was expressed as an amino-terminal fusion protein to glutathione s-transferase and as a carboxy-terminal fusion protein to a hexahistidyl tag. the expression of the fusion protein was controlled by the inducible tac promoter. under optimal conditions the immunoreactive pycsp repres ...	1997	9325141
effects of plasmodium yoelii nigeriensis infection on anopheles stephensi egg development and resorption.	it has been shown previously that infection with plasmodium yoelii nigeriensis reduces the number of eggs produced by female anopheles stephensi. here we examine the mechanism underlying fecundity reduction. ovaries from infected and uninfected (control) female mosquitoes were examined 12, 24 or 36 h after blood-feeding during the first gonotrophic cycle (replicated) or the second gonotrophic cycle (unreplicated). follicular development was assessed according to christophers' stages and the prop ...	1997	9330258
immunization against the murine malaria parasite plasmodium yoelii using a recombinant protein with adjuvants developed for clinical use.	mice vaccinated with a recombinant protein containing the two egf-like modules of plasmodium yoelii merozoite surface protein-1 in liposomes or combined with the formulations sbas2.1 and sbas2, were protected against a lethal malaria infection. the protection achieved with these adjuvants developed for clinical use was as good as or better than that achieved with freund's adjuvant. a parasite-specific response was needed for protection. analysis of the immunoglobulin sub-class response showed th ...	1997	9330469
glycosyl-phosphatidylinositols in protozoa structure, biosynthesis and intracellular localisation.	we are investigating the structure and biosynthesis of glycosyl-phosphatidylinositols (gpi) in the protozoa toxoplasma gondii, plasmodium falciparum, plasmodium yoelii and paramecium primaurelia. this comparison of structural and biosynthesis data should lead us to common and individual features of the gpi-biosynthesis and transport in different organisms.	1997	9343937
delayed migration of plasmodium sporozoites from the mosquito bite site to the blood.	studies were done on delivery of plasmodium yoelii sporozoites by anopheles stephensi into the skin of balb/c mice. when infected mosquitoes fed on a portion of the ear, 81% of these positive control mice developed parasitemia. when the fed-upon site was excised immediately or 5 min postfeeding, a highly significant, smaller percentage of these experimental mice developed parasitemia. when the delay in removal of mosquito-bitten tissue was extended to 15 min, no significant difference was found ...	1997	9347958
immunization with a recombinant c-terminal fragment of plasmodium yoelii merozoite surface protein 1 protects mice against homologous but not heterologous p. yoelii sporozoite challenge.	it has been reported previously that immunization with recombinant protein containing the two epidermal growth factor (egf)-like modules from merozoite surface protein 1 (msp-1) of plasmodium yoelii (strain ym) protects mice against a lethal blood-stage challenge with the same parasite strain. since msp-1 is expressed in both liver- and blood-stage schizonts and on the surface of merozoites, we evaluated the effectiveness of immunization with recombinant proteins containing either the individual ...	1997	9353014
studies of the hepatic mitochondrial and microsomal mixed-function oxidase system during plasmodium yoelii infection and inducer treatment in swiss albino mice.	plasmodium yoelii infection resulted in depression of hepatic mitochondrial and microsomal mixed-function oxidase system indices, e.g. cytochrome p-450, cytochrome b5 and phase ii detoxification enzyme glutathione-s-transferase, while heam and haemozoin registered a marked increase in swiss albino mice. phenobarbitone (inducer) treatment showed induced levels of hepatic mitochondrial and microsomal cytochrome p-450 and glutathione-s-transferase in normal as well as in infected mice. the induced ...	1997	9357489
the novel oxygenated chalcone, 2,4-dimethoxy-4'-butoxychalcone, exhibits potent activity against human malaria parasite plasmodium falciparum in vitro and rodent parasites plasmodium berghei and plasmodium yoelii in vivo.	previous studies have shown that licochalcone a, an oxygenated chalcone, exhibits antileishmanial and antimalarial activities. the present study was designed to examine the antimalarial activity of an analog of licochalcone a, 2,4-dimethoxy-4'-butoxychalcone (2,4mbc). 2,4mbc inhibited the in vitro growth of both a chloroquine-susceptible (3d7) and a chloroquine-resistant (dd2) strain of plasmodium falciparum in a [3h]hypoxanthine uptake assay. the in vivo activity of 2,4mbc was tested in mice in ...	1997	9359735
monoclonal antibodies multireactive with parasite antigens produced by hybridomas generated from naive mice.	hybridoma clones producing igm naturally occurring (natural) antibodies were generated from naive balb/c mice and characterized for reactivity against parasite antigens. ascites of mice injected with these hybridomas reacted with toxoplasma gondii soluble antigen at levels approximately 1000-10,000 times higher than serum pooled from mice used for generating hybridomas as determined by a conventional enzyme-linked immunosorbent assay. western blot analysis indicated that these monoclonal antibod ...	1997	9364565
synthesis and antimalarial activity in vitro and in vivo of a new ferrocene-chloroquine analogue.	the antimalarial activities of ferrocenic compounds mimicking chloroquine and active upon chloroquine-resistant strains of plasmodium falciparum were evaluated. four 7-chloro-4-[[[2-[(n,n-substituted amino)methyl]ferrocenyl]methyl]amino]quinoline derivatives have been synthesized; one of them, 1a, showed high potent antimalarial activity in vivo on mice infected with plasmodium berghei n. and plasmodium yoelii ns. and was 22 times more potent against schizontocides than chloroquine in vitro agai ...	1997	9371235
immunization with hybrid hepatitis b virus core particles carrying circumsporozoite antigen epitopes protects mice against plasmodium yoelii challenge.	the hepatitis b virus nucleocapsid antigen (hbcag) was investigated as a carrier moiety for circumsporozoite protein (cs) repeat b cell epitopes of the rodent malaria agent plasmodium yoelii. a vector expressing a hybrid gene coding for the dominant cs repeat epitope (qgpgap)4 was constructed and transformed into avirulent salmonella typhimurium. the resulting hybrid hbcag-cs polyproteins were purified from recombinant salmonella typhimurium. they purified as particles and displayed hbc as well ...	1997	9382731
the time course of selected malarial infections in cytokine-deficient mice.	murine malarial parasites have long been characterized by their requirement for either antibody-mediated immunity (ami) or cell-mediated immunity (cmi) for suppression of acute parasitemia, with plasmodium yoelii reportedly requiring ami for suppression and p. chabaudi requiring cmi. to assess this characterization in terms of the current t(h1)/t(h2)-cmi/ami hypothesis, we infected gene-targeted "knockout" mice lacking either a type-1 cytokine (il-2 or ifn-gamma) or a type-2 cytokine (il-4 or il ...	1997	9030670
evidence for superantigenic activity during murine malaria infection.	tcr v beta usage was examined in c57bl/6 mice infected with plasmodium yoelii. in addition to a polyclonal t cell activation, already described, a superantigenic-like activity was observed during the acute infection. this superantigenic activity induces a preferential deletion without prior expansion of cd4+ and cd8+ t cells bearing the tcr v beta 9 segment. the superantigen could be released by the parasite at different stages of its development since the deletion of v beta 9+ t cells was obser ...	1997	9043944
prolonged th1-like response generated by a plasmodium yoelii-specific t cell clone allows complete clearance of infection in reconstituted mice.	in the present study, we report the ability of in vitro cultured cd4+ t cells, generated following immunization with dead blood stage p. yoelii parasites, to mediate protection against homologous challenge infection in reconstituted nude mice. p. yoelii-specific t cell line cells produced ifn-gamma after in vitro stimulation with specific antigen, and were protective when adoptively transferred into athymic nude mice. following transfer p. yoelii-specific t cell lines into nude and scid mice, el ...	1997	9106817
early gamma interferon responses in lethal and nonlethal murine blood-stage malaria.	this study was undertaken to explore early differences in cytokine production during nonlethal and lethal blood-stage murine malaria infections. cytokine analysis of spleens during these infections showed that the principal difference between two nonlethal and two lethal plasmodium species was the production of gamma interferon 24 h after infection with nonlethal parasites. in contrast, no increases in interleukin-4 production were observed in the first 24 h and tumor necrosis factor alpha level ...	1997	9125535
adoptive transfer of immunity induced with chloroquine attenuated plasmodium yoelii nigeriensis from immune to immunologically naive mice.	immunity was induced in albino mice using chloroquine-attenuated plasmodium yoelii nigeriensis which had been maintained under drug pressure in 4 passages. attempts were made to adoptively transfer immunity from the immune to immunologically naive mice by means of serum, spleen and thoracic duct extracts. none of them conferred complete immunity on the recipients but some protection was gained. this was evident from the prolongation of both the pre-patent periods of the infection and the surviva ...	1997	9133824
the effect of plasmodium yoelii nigeriensis infection on ovarian protein accumulation by anopheles stephensi.	both anopheline and culicine mosquitoes have been shown to incur a reduction in reproductive fitness when infected with malaria parasites. the agent of rodent malaria, plasmodium yoelii nigeriensis, was used as a laboratory model to investigate changes in the accumulation of protein in the ovaries of anopheles stephensi when infected with oocysts or when feeding on mice with heavy asexual parasitaemia but no mature gametocytes. herein we report that during the early phases of the gonotrophic cyc ...	1997	9134561
single immunizing dose of recombinant adenovirus efficiently induces cd8+ t cell-mediated protective immunity against malaria.	the immunogenicity of a recombinant replication defective adenovirus expressing a major malaria ag, the circumsporozoite (cs) protein (adpycs), was determined using a rodent malaria model. a single immunizing dose of this construct induced a large number of cs-specific cd8+ and cd4+ t cells in the spleens of these animals, particularly when given by the s.c. or i.m. route. a single dose of adpycs also induced high titers of abs to plasmodium yoelii sporozoites in mice. no other form of presentat ...	1997	9013969
atovaquone, a broad spectrum antiparasitic drug, collapses mitochondrial membrane potential in a malarial parasite.	at present, approaches to studying mitochondrial functions in malarial parasites are quite limited because of the technical difficulties in isolating functional mitochondria in sufficient quantity and purity. we have developed a flow cytometric assay as an alternate means to study mitochondrial functions in intact erythrocytes infected with plasmodium yoelii, a rodent malaria parasite. by using a very low concentration (2 nm) of a lipophilic cationic fluorescent probe, 3,3'dihexyloxacarbocyanine ...	1997	9020100
vitamin e-deficient diets enriched with fish oil suppress lethal plasmodium yoelii infections in athymic and scid/bg mice.	mice fed vitamin e-deficient diets containing omega-3 fatty acids survive infection with lethal plasmodium yoelii. the current study sought to determine if antimalarial t- and b-cell responses were required for such dietary-mediated protection. in the first set of experiments, nu/nu mice (which lack alphabeta t-cell-receptor-positive t cells and do not produce antimalarial antibody) and nu/+ mice were fed casein-based diets containing 4% menhaden oil, with or without vitamin e supplementation, f ...	1997	8975912
sterile protection of monkeys against malaria after administration of interleukin-12.	an estimated 300-500 million new infections and 1.5-2.7 million deaths attributed to malaria occur annually in the developing world, and every year tens of millions of travelers from countries where malaria is not transmitted visit countries with malaria. because the parasites that cause malaria have developed resistance to many antimalarial drugs, new methods for prevention are required. intraperitoneal injection into mice of one dose of 150 ng (approximately 7.5 micrograms per kg body weight) ...	1997	8986746
characterization of simian malarial parasite (plasmodium knowlesi)-induced putrescine transport in rhesus monkey erythrocytes. a novel putrescine conjugate arrests in vitro growth of simian malarial parasite (plasmodium knowlesi) and cures multidrug resistant murine malaria (plasmodium yoelii) infection in vivo.	a stage-dependent increase in the level of putrescine, spermidine, and spermine during intraerythrocytic growth of plasmodium knowlesi in rhesus monkey erythrocytes was observed. further, intraerythrocytic p. knowlesi-induced putrescine influx was found in trophozoite stage-infected erythrocytes and process was time- and temperature-dependent and showed saturable kinetics. characteristics of induced putrescine influx appears in infected erythrocytes to be close to the normal erythrocytes in term ...	1997	9153195
multiple antigen constructs (macs): induction of sterile immunity against sporozoite stage of rodent malaria parasites, plasmodium berghei and plasmodium yoelii.	we prepared multiple antigen constructs (macs) using circumsporozoite (cs) protein-based b-epitopes from plasmodium berghei, (ppppnpnd)2 and plasmodium yoelii, (qgpgap)3qg, along with a p. berghei t-helper epitope kqirdsiteews. mice were immunized with individual macs in oil-in-water or water-in-oil vehicles containing block copolymer (p1005) and detoxified ralps (ralps) as well as other adjuvants. sporozoite challenge results demonstrated that macs in adjuvant could induce antibodies capable of ...	1997	9160515
two antigens on zygotes and ookinetes of plasmodium yoelii and plasmodium berghei that are distinct targets of transmission-blocking immunity.	we have developed transmission-blocking monoclonal antibodies (mabs) against plasmodium yoelii 21-kda (pys21) and 28-kda (pys25) ookinete surface proteins. these mabs block infectivity of p. yoelii to anopheles stephensi. one mab, 14, cross-reacted by western blotting with a 28-kda surface protein (pbs25) of p. berghei ookinetes and blocked oocyst development, as assayed by direct mosquito feeds on passively immunized p. berghei-infected mice. in total, we have identified two ookinete surface pr ...	1997	9169761
premature removal of uninfected erythrocytes during malarial infection of normal and immunodeficient mice.	anaemia during blood-stage plasmodial infections is known to be due to at least three mechanisms: direct destruction of erythrocytes by the intra-erythrocytic parasite, inhibition of erythropoiesis, and premature removal of uninfected erythrocytes. the removal of the uninfected erythrocytes is considered by many to be dependent on an antibody-mediated mechanism. our investigations involving normal, severe combined immunodeficient (scid) and nude balb/c mice and the murine malaria parasite plasmo ...	1997	9182894
plasmodium yoelii: resistance to disease is linked to the mtv-7 locus in balb/c mice.	we have identified congenic mouse strains that differ dramatically in resistance to infection with the murine malaria parasite plasmodium yoelii 17x. after infection, balb/c mice develop severe anemia and a high degree of parasitemia which sometimes results in death. the mtv-7 congenic strain balb.d2.mlsa, however, develops only a mild degree of anemia and parasitemia. in this paper we describe the course of the disease and discuss the potential role of mtv-7 and linked loci in control of this i ...	1997	9207740
role of macrophages as possible transporters of plasmodium yoelii nigeriensis merozoites through the lymphatic system. preliminary note.	vesicles containing apparently healthy merozoites from mature schizonts were observed in the spleen and lymph nodes of mice parasitized by plasmodium yoelii nigeriensis. they differed from all parasitic stages undergoing digestion by the macrophage and from mature schizonts of the blood. up to 40 merozoites from three mature schizonts may be seen in the same compartment. they are thought to be accumulations of latent merozoites.	1997	9208034
comparison of plasmodium yoelii ookinete surface antigens with human and avian malaria parasite homologues reveals two highly conserved regions.		1997	9233679
strategy for development of a pre-erythrocytic plasmodium falciparum dna vaccine for human use.	data generated in the plasmodium yoelii rodent model indicated that plasmid dna vaccines encoding the p.yoelii circumsporozoite protein (pycsp) or 17 kda hepatocyte erythrocyte protein (pyhep17) were potent inducers of protective cd8+ t cell responses directed against infected hepatocytes. immunization with a mixture of these plasmids circumvented the genetic restriction of protective immunity and induced additive protection. a third dna vaccine encoding the p. yoelii sporozoite surface protein ...	1997	9234529
comparison of protection induced by immunization with recombinant proteins from different regions of merozoite surface protein 1 of plasmodium yoelii.	vaccination with native full-length merozoite surface protein 1 (msp1) or with recombinant c-terminal peptides protects mice against lethal challenge with virulent malaria parasites. to determine whether other regions of msp1 can also induce protection, plasmodium yoelii msp1 was divided into four separate regions. each was expressed in escherichia coli as a fusion protein with glutathione s-transferase (gst). the n-terminal fragment began after the cleavage site for the signal sequence and ende ...	1997	9234750