| linear and multiple antigen peptides containing defined t and b epitopes of the plasmodium yoelii circumsporozoite protein: antibody-mediated protection and boosting by sporozoite infection. | we previously reported the identification of a t cell epitope in the n-terminal part of the circumsporozoite protein (csp) of plasmodium yoelii yoelii (pyy). cd4+ t cell clones derived from mice immunized with a 21-mer peptide (amino acids 59-79, referred to as py1) containing this epitope confer complete protection after passive transfer in mice. these clones proliferate in vitro in the presence of a 13-mer peptide (amino acids 59-71, referred to as py1t). this shorter peptide was found to beha ... | 1997 | 9466309 |
| induced immunity to plasmodium yoelli nigeriensis in albino mice by antigenic mice organs. | antigenic materials prepared from parasite infected and non-infected tissue (blood), organs (spleen, liver, lung) and whole mouse burnt with or without aframomum melegmeta (alligator pepper) were tested whether they could elicit immune response to plasmodium yoelli nigeriensis in albino mice. this investigation is in line with the practice of traditional medicine in the western part of nigeria where burnt herbal preparation are introduced into patient through body cuts known as "gbere" for prote ... | 1997 | 9487431 |
| microvascular hemodynamics and in vivo evidence for the role of intercellular adhesion molecule-1 in the sequestration of infected red blood cells in a mouse model of lethal malaria. | the cytoadherence of infected red blood cells (irbcs) to the vascular endothelium is the major cause of irbc sequestration and vessel blockage in the cerebral form of human malaria. among the rodent models of malaria, plasmodium yoelii 17xl-infected mice show many similarities with the human cerebral malaria caused by p. falciparum. in both, the sequestration of irbcs in the brain vessels is secondary to the cytoadherence of irbcs to the vascular endothelium. similar to p. falciparum infection i ... | 1998 | 9502610 |
| potential inhibitors of plasmodial heme oxygenase; an innovative approach for combating chloroquine resistant malaria. | syntheses of imidazo-pyridines and substituted prolines and their effect on heme oxygenase activity of plasmodium yoelii and corresponding infected host have been studied. six compounds in vitro and one in vivo showed selective inhibition of parasite enzyme which may be further exploited in the development of resistant reversal agents. | 1998 | 9547941 |
| status of urea and related enzymes during plasmodium yoelii infection and pyrimethamine treatment in mice. | plasmodium yoelii infection alters the hepatic levels of key enzymes of urea cycle, viz.carbamoyl phosphates synthetase (ec 6.3.4.16) and ornithine transcarbamoylase (ec 2.1.3.3) and urea levels in mice. the urea level was found elevated in liver, brain and plasma during p. yoelii infection. however, carbamoyl phosphate synthetase and ornithine transcarbamoylase were noticeably decreased during p. yoelii infection. pyrimethamine treatment (10 mg/kg body weight for 4 days) brought back the altere ... | 1997 | 9567749 |
| plasmodium yoelii: differences in the transcription of the 235-kda rhoptry protein multigene family in lethal and nonlethal lines. | we have compared the transcription of the 235-kda rhoptry protein (p235) multigene family in the lethal (ym) and nonlethal (17x) lines of the rodent malaria parasite plasmodium yoelii. this protein is thought to be involved in erythrocyte invasion by the parasite. using a pcr-based approach we demonstrated that both lines have similar p235 families. however, rt-pcr analysis revealed that this similarity is not evident at the level of transcription, with the lethal line not transcribing a whole s ... | 1998 | 9603488 |
| induction of protective immune responses by immunization with linear multiepitope peptides based on conserved sequences from plasmodium falciparum antigens. | a cysteine-containing peptide motif, ewspcsvtcg, is found highly conserved in the circumsporozoite protein (csp) and the thrombospondin-related anonymous protein (trap) of all the plasmodium species analyzed so far and has been shown to be crucially involved in the sporozoite invasion of hepatocytes. we have recently shown that peptide sequences containing this motif, and also the antibodies raised against the motif, inhibit the merozoite invasion of erythrocytes. however, during natural infecti ... | 1998 | 9632590 |
| protection of mice against plasmodium yoelii sporozoite challenge with p. yoelii merozoite surface protein 1 dna vaccines. | immunization of mice with dna vaccines encoding the full-length form and c and n termini of plasmodium yoelii merozoite surface protein 1 provided partial protection against sporozoite challenge and resulted in boosting of antibody titers after challenge. in c57bl/6 mice, two dna vaccines provided protection comparable to that of recombinant protein consisting of the c terminus in freund's adjuvant. | 1998 | 9632624 |
| boosting with recombinant vaccinia increases immunogenicity and protective efficacy of malaria dna vaccine. | to enhance the efficacy of dna malaria vaccines, we evaluated the effect on protection of immunizing with various combinations of dna, recombinant vaccinia virus, and a synthetic peptide. immunization of balb/c mice with a plasmid expressing plasmodium yoelii (py) circumsporozoite protein (csp) induces h-2kd-restricted cd8+ cytotoxic t lymphocyte (ctl) responses and cd8+ t cell- and interferon (ifn)-gamma-dependent protection of mice against challenge with py sporozoites. immunization with a mul ... | 1998 | 9636204 |
| causal prophylactic activity of antihistaminic agents against plasmodium yoelii nigeriensis infection in swiss mice. | the causal prophylactic activity of five tricyclic anti-histaminic agents (histamine h1-receptor antagonists) cyproheptadine, ketotifen, loratadine, azatadine and terfenadine was evaluated in an experimental murine malaria model. sporozoite induced infections with plasmodium yoelii nigeriensis (n-67), a strain innately resistant to choloroquine, were employed for the efficacy test and pyrimethamine and primaquine were used as standard reference drugs. treatment with cyproheptadine or ketotifen a ... | 1998 | 9638277 |
| amino acid transport in cerebral microvessels during plasmodium yoelii infection in mice. | plasmodium yoelii infected cerebral microvessels of mice had an enhanced time-dependent, temperature-sensitive, and saturable uptake of [14c]-amino acid. viz. leucine, valine and glycine. metabolic inhibitors caused a noticeable inhibition of amino acid uptake in normal microvessels as compared to infected cerebral microvessels indicating that the uptake of [14c]-l-leucine, [14c]-l-valine and [14c]-glycine is an energy dependent process. | 1997 | 9641523 |
| definition of t cell epitopes within the 19 kda carboxylterminal fragment of plasmodium yoelii merozoite surface protein 1 (msp1(19)) and their role in immunity to malaria. | msp1(19) is one of the leading malaria vaccine candidates. however, the mechanism of protection is not clear. to determine whether msp1(19)-specific effector t cells can control parasitaemia, we analysed the specificity of t cells induced following immunization with recombinant forms of p. yoelii msp1(19) and asked whether they could protect mice. there was no evidence that effector t cells were capable of protecting since: (1) immunization of mice with ymsp1(19), but not defined epitopes, was a ... | 1998 | 9651928 |
| recombinant sindbis viruses expressing a cytotoxic t-lymphocyte epitope of a malaria parasite or of influenza virus elicit protection against the corresponding pathogen in mice. | subcutaneous administration in mice of recombinant sindbis viruses expressing a class i major histocompatibility complex-restricted 9-mer epitope of the plasmodium yoelii circumsporozoite protein or the nucleoprotein of influenza virus induces a large epitope-specific cd8(+) t-cell response. this immunization also elicits a high degree of protection against infection with malaria or influenza a virus. | 1998 | 9658144 |
| passive immunization with antibodies against three distinct epitopes on plasmodium yoelii merozoite surface protein 1 suppresses parasitemia. | we have produced monoclonal antibodies against plasmodium yoelii merozoite surface protein 1 (msp-1) and have assessed their ability to suppress blood stage parasitemia by passive immunization. six immunoglobulin g antibodies were characterized in detail: three (b6, d3, and f5) were effective in suppressing a lethal blood stage challenge infection, two (b10 and g3) were partially effective, and one (b4) was ineffective. msp-1 is the precursor to a complex of polypeptides on the merozoite surface ... | 1998 | 9673281 |
| isolation of merozoite rhoptries, identification of novel rhoptry-associated proteins from plasmodium yoelii, p. chabaudi, p. berghei, and conserved interspecies reactivity of organelles and proteins with p. falciparum rhoptry-specific antibodies. | rhoptries were isolated from merozoites of p. yoelii (17 xl), p. chabaudi adami and p. berghei (k-173), using sucrose gradient density centrifugation. mouse antisera was prepared against the organelles and characterized. antibodies specific for a known p. yoelii rhoptry protein were used to identify gradient fractions containing rhoptries and electron microscopy was used to confirm rhoptry enrichment and organelle morphology. western blotting analysis of the gradients with organelle-specific ant ... | 1998 | 9676705 |
| fc receptors are not required for antibody-mediated protection against lethal malaria challenge in a mouse model. | the mechanisms by which abs mediate protection during blood-stage malaria infections is controversial, with some evidence pointing to the direct effect of abs on parasite invasion and growth, while other studies suggest that abs act in cooperation with monocytes to achieve parasite inhibition. to determine whether the effector phase of protection in vivo to the rodent parasite plasmodium yoelii yoelii requires fc receptor bearing cells, we passively transferred immune sera into fcr gamma-chain k ... | 1998 | 9712060 |
| a plasmid encoding murine granulocyte-macrophage colony-stimulating factor increases protection conferred by a malaria dna vaccine. | using the murine parasite plasmodium yoelii (py) as a model for malaria vaccine development, we have previously shown that a dna plasmid encoding the py circumsporozoite protein (pycsp) can protect mice against sporozoite infection. we now report that mixing a new plasmid pycsp1012 with a plasmid encoding murine granulocyte-macrophage colony-stimulating factor (gm-csf) increases protection against malaria, and we have characterized in detail the increased immune responses due to gm-csf. pycsp101 ... | 1998 | 9725227 |
| recombinant mycobacterium bovis bacillus calmette-guérin secreting merozoite surface protein 1 (msp1) induces protection against rodent malaria parasite infection depending on msp1-stimulated interferon gamma and parasite-specific antibodies. | the merozoite surface protein 1 (msp1) has emerged as a leading malaria vaccine candidate at the erythrocytic stage. recombinant bacillus calmette-guérin (rbcg), which expressed a cooh-terminal 15-kd fragment of msp1 of plasmodium yoelii (msp1-15) as a fusion protein with a secretory protein of mycobacterium kansasii, was constructed. immunization of mice with this rbcg induced a higher degree of protection against blood-stage parasite infection than with recombinant msp1-15 in the ribi adjuvant ... | 1998 | 9730886 |
| rodent malaria prophylaxis by transdermal delivery of primaquine. | the efficacy of a new transdermal delivery system of primaquine in order to obtain causal prophylaxis against sporozoite-induced plasmodium yoelii infection was evaluated. a single administration of a 1.0 cm2 transdermal delivery system containing 5.0 mg of primaquine was able to protect 100% of treated mice. this result suggests that the transdermal route may be a very interesting approach for malaria prophylaxis and should encourage further studies in order to determine the absolute bioavailab ... | 1998 | 9762576 |
| divergent evolutionary constraints on mitochondrial and nuclear genomes of malaria parasites. | genetic variation among malaria parasites has important consequences with regard to drug resistance, pathogenicity, immunity, transmission, and speciation. in this regard, malaria parasites have been shown to display a high degree of inter- and intra-species genetic divergence. the nuclear genomes of plasmodium falciparum, plasmodium yoelii, and plasmodium gallinaceum are vastly divergent yet share a similar codon usage and total a/t content of approximately 82%. this is in contrast to other pri ... | 1998 | 9763290 |
| intranasal immunization with yeast-expressed 19 kd carboxyl-terminal fragment of plasmodium yoelii merozoite surface protein-1 (ymsp119) induces protective immunity to blood stage malaria infection in mice. | variable protection against malaria blood-stage infection has been demonstrated in mice following parenteral immunization with the highly conserved 19 kd carboxylterminal fragment of the merozoite surface protein-1 (msp119) using cfa/ifa and other adjuvants. here we show that intranasal immunization of balb/c mice with yeast expressed plasmodium yoelii msp119 plus a mixture of native and recombinant cholera toxin b subunit, could induce serum msp119-specific antibodies at titres ranging from 20 ... | 1998 | 9767608 |
| comparison of humoral immune responses elicited by dna and protein vaccines based on merozoite surface protein-1 from plasmodium yoelii, a rodent malaria parasite. | immunization with dna vaccines encoding relevant ags can induce not only cell-mediated immune response but also humoral immune responses against pathogenic microorganisms in several animal models. our previous results demonstrated that, when the c terminus (pyc2) of plasmodium yoelii merozoite surface protein-1 (msp-1), a leading vaccine candidate against erythrocytic stages of malaria, was expressed as a fusion protein (gst-pyc2) with glutathione s-transferase (gst), it elicited ab-mediated pro ... | 1998 | 9780195 |
| efficient induction of protective anti-malaria immunity by recombinant adenovirus. | the immunogenicity of a previously constructed replication-defective recombinant adenovirus expressing the cs protein of plasmodium yoelii was compared with that of irradiated sporozoites. we found that immunization of balb/c mice with a single dose of this recombinant adenovirus induced a much greater cs-specific t-cell response compared with immunization with irradiated sporozoites. more importantly, we found that this recombinant adenovirus induces similar or higher levels of protective immun ... | 1998 | 9795385 |
| plasmodium yoelii: identification of rhoptry proteins using monoclonal antibodies. | thirteen monoclonal antibodies, obtained after immunization of mice with plasmodium yoelii schizonts, were selected using immunofluorescence assay: they all presented typical fluorescence patterns of rhoptries. this antigen localization was confirmed by immunoelectron microscopy. the molecular weights of the recognized antigens are 68, 80, 105, 130 and 140 kda as determined by immunoprecipitation and immunoblot under reducing and nonreducing conditions. these values are very similar to these of ... | 1998 | 9806867 |
| effect of plasmodium yoelii nigeriensis (haemosporidia: plasmodiidae) on anopheles stephensi (diptera: culicidae) vitellogenesis. | our previous studies demonstrated a significant reduction in the egg production and survival of anopeles stephensi liston infected with plasmodium yoelii nigeriensis killick-kendrick. we investigated the physiological mechanism underlying the malaria-induced curtailment of reproductive fitness. polyclonal antibodies were raised against an. stephensi vitellin (vn) and used in an enzyme immunoassay to quantify ovarian vn and hemolymph vitellogenin (vg) at 8, 12, 16, 20, 24, and 48 h postblood feed ... | 1998 | 9835686 |
| plasmodium yoelii ym maebl protein is coexpressed and colocalizes with rhoptry proteins. | we have previously cloned genes from multiple rodent malaria species exhibiting characteristics of the genes encoding duffy binding like-erythrocyte binding proteins (dbl-ebp). homology is seen in the intron/exon structure of the genes and in the carboxyl terminal region (including the deduced carboxyl cysteine-rich domain) of the proteins they encode. however, the amino termini of these proteins are not homologous to the dbl-ebp but contain tandem cysteine-rich regions that are similar to the c ... | 1998 | 9851604 |
| murine gamma delta t lymphocytes elicited during plasmodium yoelii infection respond to plasmodium heat shock proteins. | gamma delta t cells accumulate during plasmodium infections in both murine and human malarias. the biological role of these cells and the antigens that they recognize are not clearly understood, although recent findings indicate that gamma delta t cells in general influence both innate and antigen-specific adaptive host responses. we examined the accumulation of gamma delta t cells elicited during infection with virulent and avirulent plasmodium yoelii parasites in relatively susceptible and res ... | 1999 | 9864196 |
| correlation of increased expression of intercellular adhesion molecule-1, but not high levels of tumor necrosis factor-alpha, with lethality of plasmodium yoelii 17xl, a rodent model of cerebral malaria. | previous studies demonstrated that plasmodium yoelii 17xl, a lethal strain of rodent malaria, causes a syndrome in sw mice that resembles human cerebral malaria. the mouse brain pathology is characterized by cytoadherence of parasitized erythrocytes. here, the possible mechanisms mediating cerebral malaria in this model were studied and the results were compared with a nonlethal strain of this parasite, p. yoelii 17xnl (nonlethal), which does not cause cerebral malaria. immunostaining for interc ... | 1998 | 9886187 |
| protective immunization with a novel membrane protein of plasmodium yoelii-infected erythrocytes. | immunization with a particulate fraction of blood-stage antigens was shown previously to protect mice against plasmodium yoelii malaria. to identify antigens inducing the protective response, sera from immunized mice were used to screen a p. yoelii cdna expression library. sequence analysis of one 2.6-kb cdna clone indicated that the identified gene, pypag-1, encoded a novel plasmodial antigen. two nonoverlapping regions of pypag-1 were expressed in escherichia coli. the first recombinant antige ... | 1999 | 9916076 |
| plasmodium: immunization with carboxyl-terminal regions of msp-1 protects against homologous but not heterologous blood-stage parasite challenge. | a leading candidate for a vaccine targeted at the erythrocytic stages of plasmodial parasite development is the merozoite surface protein-1 (msp-1). we have previously shown that the carboxyl-terminal region of msp-1 derived from plasmodium yoelii yoelii 17xl, expressed as a fusion protein with glutathione s-transferase (gst-pyc2), can immunize mice against an otherwise lethal homologous challenge infection. this protection has been shown to be predominantly mediated by antibodies. we report her ... | 1999 | 9920045 |
| plasmodium berghei and plasmodium yoelii: molecular karyotypes of drug-resistant lines. | | 1999 | 9920047 |
| plasmodium falciparum and plasmodium yoelii: effect of the iron chelation prodrug dexrazoxane on in vitro cultures. | to determine if an iron-chelating prodrug that must undergo intracellular hydrolysis to bind iron has antimalarial activity, we examined the action of dexrazoxane on plasmodium falciparum cultured in human erythrocytes and p. yoelii cultured in mouse hepatocytes. dexrazoxane was recently approved to protect humans from doxorubucin-induced cardiotoxicity. using the fluorescent marker calcein, we confirmed that the iron-chelating properties of dexrazoxane are directly related to its ability to und ... | 1999 | 9990337 |
| final stage of maturation of the erythrocytic schizonts of rodent plasmodium in the lungs. | schizonts of all rodent plasmodium studied (plasmodium yoelii, p. chabaudi, p. vinckei) show a characteristic morphology when they are completely mature: rounded or slightly elongate merozoites, completely detached from the pigment mass. at this stage, they are localized principally in the spleen and the lungs but, in impression smears of these organs they show two different aspects. in the spleen, schizonts are either inside the host erythrocyte or extraglobular but still close to a pigment mas ... | 1999 | 10047954 |
| induction of cd8+ t cell-mediated protective immunity against trypanosoma cruzi. | trypanosoma cruzi was transformed with the plasmodium yoelii gene encoding the circum-sporozoite (cs) protein, which contains the well-characterized cd8+ t cell epitope, syvpsaeqi. in vivo and in vitro assays indicated that cells infected with the transformed t. cruzi could process and present this malaria parasite-derived class i mhc-restricted epitope. immunization of mice with recombinant influenza and vaccinia viruses expressing the syvpsaeqi epitope induced a large number of specific cd8+ t ... | 1999 | 10069411 |
| pan dr binding sequence provides t-cell help for induction of protective antibodies against plasmodium yoelii sporozoites. | pan-dr epitope (padre) peptides have demonstrated the capacity to deliver help for antibody responses in vivo. they were also found, fortuitously, to be able to provide significant helper t-cell activity in vivo. this suggested that linear constructs, containing the padre epitope, might be as efficient at generating an immune response as large multivalent antigens. plasmodium falciparum and p. yoelii padre constructs were capable of inducing a high titre igg antibody response that recognized int ... | 1999 | 10195633 |
| expression of disulphide-bridge-dependent conformational epitopes and immunogenicity of the carboxy-terminal 19 kda domain of plasmodium yoelii merozoite surface protein-1 in live attenuated salmonella vaccine strains. | the 19 kda carboxy-terminal domain of plasmodium yoelii merozoite surface protein-1 (msp1(19)) was expressed in salmonella vaccine strains as a carboxy-terminal fusion to fragment c of tetanus toxin (tetc). this study demonstrates that antibodies that recognize disulphide-dependent conformational epitopes in native msp1 react with the tetc-msp1(19) fusion protein expressed in salmonella. the proper folding of msp1(19) polypeptide is dependent on both the salmonella host strain and the protein to ... | 1999 | 10206702 |
| plasmodium chabaudi chabaudi: effect of low parasitemias on immunity in cb6f1 mice. | we examined the effect that low parasitemias have on the immune response of cb6f1 mice infected with plasmodium chabaudi chabaudi as. ascending parasitemias were stopped by chloroquine treatment when they were between 1.6 and 9.4%. mice that suffered low parasitemias developed good immunity to homologous reinfection but, contrary to what happened in mice that suffered full parasitemias, they did not develop immunity to heterologous reinfection with plasmodium yoelii 17xl. total igg antiparasite ... | 1999 | 10329368 |
| chromosomal organisation of a gene family encoding rhoptry proteins in plasmodium yoelii. | the genomic organisation of the genes coding for a group of high molecular mass rhoptry proteins of the rodent malaria parasite plasmodium yoelii ym was investigated using blotting, two dimensional gel electrophoresis and restriction fragment length analysis. the genes were found on chromosomes 1, 5, 6 and 10, with the possibility that related genes were also present on chromosomes 3 and 4. on chromosome 1 the genes were located close to one end, whereas they were present at both ends of chromos ... | 1999 | 10340483 |
| absolute requirement for an active immune response involving b cells and th cells in immunity to plasmodium yoelii passively acquired with antibodies to the 19-kda carboxyl-terminal fragment of merozoite surface protein-1. | vaccination of mice with the leading malaria vaccine candidate homologue, the 19-kda carboxyl terminus of merozoite surface protein-1 (msp119), results in sterile immunity to plasmodium yoelii, with no parasites detected in blood. although such immunity depends upon high titer abs at challenge, high doses of immune sera transferred into naive mice reduce parasitemia (and protect from death) but do not result in a similar degree of protection (with most mice experiencing high peak parasitemias); ... | 1999 | 10358180 |
| effects of nitroquine on ultrastructures and cytochrome oxidase of exoerythrocytic plasmodium yoelii in rat liver. | to study the effects of nitroquine acetate (na) on the ultrastructures and cytochrome-c oxidase (cco) of exoerythrocytic forms (eef) of plasmodium yoelii. | 1998 | 10375793 |
| theileria parva 104 kda microneme--rhoptry protein is membrane-anchored by a non-cleaved amino-terminal signal sequence for entry into the endoplasmic reticulum. | the 104 kda microneme-rhoptry protein (p104) is the only known apical complex organelle-specific protein of theileria parva. p104 exhibits striking structural similarities to circumsporozoite protein and sporozoite surface protein 2 of plasmodium yoelii. their primary sequences contain two hydrophobic segments, located at the amino-and the carboxy-terminus. the p104 amino-terminal hydrophobic region was suggested to be a signal peptide for entry into the endoplasmic reticulum and the extreme car ... | 1999 | 10376990 |
| artemisinin, an endoperoxide antimalarial, disrupts the hemoglobin catabolism and heme detoxification systems in malarial parasite. | endoperoxide antimalarials based on the ancient chinese drug qinghaosu (artemisinin) are currently our major hope in the fight against drug-resistant malaria. rational drug design based on artemisinin and its analogues is slow as the mechanism of action of these antimalarials is not clear. here we report that these drugs, at least in part, exert their effect by interfering with the plasmodial hemoglobin catabolic pathway and inhibition of heme polymerization. in an in vitro experiment we observe ... | 1999 | 10383451 |
| splenic and hepatic hemozoin in mice after malaria parasite clearance. | hemozoin (malaria pigment) is found in many tissues during malaria infections. in mice that have self-cured from plasmodium yoelii and plasmodium chabaudi infections, liver hemozoin concentration and total content decreased for 6-9 mo after parasite clearance. however, both spleen hemozoin concentration and total hemozoin content increased dramatically during this time period. thus, hemozoin or hemozoin-laden macrophages continue to accumulate in murine spleens for at least several months after ... | 1999 | 10386458 |
| studies on hepatic oxidative stress and antioxidant defence system during chloroquine/poly iclc treatment of plasmodium yoelii nigeriensis infected mice. | reactive oxygen species are important mediators of tissue injury during malaria infection. the status of hepatic oxidative stress and antioxidant defence indices were studied during plasmodium yoelii nigeriensis (p. y. nigeriensis) infection and chloroquine/ polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (poly iclc) treatment of infected mice. p. y. nigeriensis infection resulted in a significant increase in oxidative stress indices viz., xanthine oxidase a ... | 1999 | 10391138 |
| il-12 and nk cells are required for antigen-specific adaptive immunity against malaria initiated by cd8+ t cells in the plasmodium yoelii model. | cd8+ t cells have been implicated as critical effector cells in protection against preerythrocytic stage malaria, including the potent protective immunity of mice and humans induced by immunization with radiation-attenuated plasmodium spp. sporozoites. this immunity is directed against the plasmodium spp. parasite developing within the host hepatocyte and for a number of years has been presumed to be mediated directly by cd8+ ctl or indirectly by ifn-gamma released from cd8+ t cells. in this pap ... | 1999 | 10395683 |
| gamma delta t-cells may interfere with a productive immune response in plasmodium yoelii infections. | mice lacking alpha beta t-cells or gamma delta t-cells were infected with plasmodium yoelii 17x nl (non-lethal) and followed for parasitaemia and cytokine production. while the parasitaemia in wild type mice resolved after reaching a peak value of 30 to 50%, it persisted in the -alpha beta t-cell mice until death. however, in the -gamma delta t-cell mice the peak parasitaemia was 12.5% of the levels seen in the wild type and -alpha beta t-cell mice and resolved faster than in the wild type mice. ... | 1999 | 10404269 |
| immunization with heat-killed toxoplasma gondii stimulates an early ifn-gamma response and induces protection against virulent murine malaria. | in this study, we describe protection of balb/c mice by immunization with heat-killed t. gondii tachyzoites against infection with plasmodium yoelii 17xl which causes cerebral malaria and death in mice by day 7-8 post infection. immunization resulted significant reduction in parasitemia at the peak period of infection. protection induced by heat-killed t. gondii was associated with marked increase in nk cell number and ifn-gamma mrna expression early in the infection. the level of ifn-gamma or t ... | 1999 | 10418909 |
| morphological analysis of isolated rhoptries from plasmodium yoelii, p. berghei, and p. chabaudi merozoites. | | 1999 | 10425155 |
| codon optimization effect on translational efficiency of dna vaccine in mammalian cells: analysis of plasmid dna encoding a ctl epitope derived from microorganisms. | interspecific difference of codon usage is one of the major obstacles for effective induction of specific immune responses against bacteria and protozoa by dna immunization. using genes encoding major histocompatibility complex class i-restricted cytotoxic t-lymphocyte (ctl) epitopes, derived from an intracellular bacterium, listeria monocytogenes and a mouse malaria parasite, plasmodium yoelii, we report here that the codon optimization level of the genes is not precisely proportional to, but d ... | 1999 | 10425204 |
| resistance mutations reveal the atovaquone-binding domain of cytochrome b in malaria parasites. | atovaquone represents a class of antimicrobial agents with a broad-spectrum activity against various parasitic infections, including malaria, toxoplasmosis and pneumocystis pneumonia. in malaria parasites, atovaquone inhibits mitochondrial electron transport at the level of the cytochrome bc1 complex and collapses mitochondrial membrane potential. in addition, this drug is unique in being selectively toxic to parasite mitochondria without affecting the host mitochondrial functions. a better unde ... | 1999 | 10447880 |
| studies on hepatic oxidative stress and antioxidant defence systems during arteether treatment of plasmodium yoelii nigeriensis infected mice. | reactive oxygen species play an important role in pathology during malaria infection. the status of hepatic oxidative stress and antioxidant defence indices was studied during plasmodium yoelii nigeriensis (p. y. nigeriensis) infection in mice and arteether treatment of p. y. nigeriensis infected mice. p. y. nigeriensis infection caused a significant increase in hepatic xanthine oxidase, rate of lipid peroxidation, reduced glutathione (gsh) and glutathione reductase with progressive rise in para ... | 1999 | 10448917 |
| macrophages expressing heat-shock protein 65 play an essential role in protection of mice infected with plasmodium yoelii. | c57bl/6 (b6) mice are resistant to infection with the non-lethal (nl) strain of plasmodium yoelii 17x, while being susceptible to that with the lethal (l) strain. the 65 000 mw heat-shock protein (hsp 65) was strongly expressed in splenic adherent cells of b6 mice 10 days after infection with the nl strain of p. yoelii but only slightly in those from mice infected with the l strain. mice which had survived infection with the nl strain were resistant to challenge with the l strain and hsp 65 was ... | 1999 | 10457214 |
| prolonged expression of ifngamma induced by protective blood-stage immunization against plasmodium yoelii malaria. | mice vaccinated with whole blood-stage antigens of plasmodium yoelii develop protective, antibody-mediated immune responses to homologous challenge infection. in this model the level of protection induced by whole parasite antigen vaccination is dependent on antibody isotype, which can be influenced by adjuvant formulations. in this study the ability adjuvant formulations to affect cytokine production and protection against p. yoelii blood-stage infection was investigated. survival of mice in gr ... | 1999 | 10501247 |
| stage-specific expression of heat shock protein 90 in murine malaria parasite plasmodium yoelii. | | 1999 | 10502467 |
| the effect of plasmodium yoelii nigeriensis infection on the feeding persistence of anopheles stephensi liston throughout the sporogonic cycle. | vector-borne parasites such as malaria have been shown to modify the feeding behaviour of their invertebrate hosts so as to increase the probability of transmission. however, evolutionary consideration of developmental changes in malaria within anopheles mosquitoes suggests that the nature of altered feeding by mosquitoes should differ depending on the developmental stage of the parasite. we present laboratory evidence that the feeding persistence of female anopheles stephensi towards a human ho ... | 1999 | 10518321 |
| cd4(+) t-cell- and gamma interferon-dependent protection against murine malaria by immunization with linear synthetic peptides from a plasmodium yoelii 17-kilodalton hepatocyte erythrocyte protein. | most work on protective immunity against the pre-erythrocytic stages of malaria has focused on induction of antibodies that prevent sporozoite invasion of hepatocytes, and cd8(+) t-cell responses that eliminate infected hepatocytes. we recently reported that immunization of a/j mice with an 18-amino-acid synthetic linear peptide from plasmodium yoelii sporozoite surface protein 2 (ssp2) in titermax adjuvant induces sterile protection that is dependent on cd4(+) t cells and gamma interferon (ifn- ... | 1999 | 10531206 |
| long-lasting protective immunity against rodent malaria parasite infection at the blood stage by recombinant bcg secreting merozoite surface protein-1. | previously, we constructed a recombinant live bcg (rbcg) secreting a 15 kda c-terminal region of msp-1 from plasmodium yoelii (msp-1(15)) and succeeded in the induction of more efficient protective immunity against parasite infection than observed with artificial adjuvants (matsumoto s, yukitake h, kanbara h, yamada t. recombinant mycobacterium bovis bacillus calmette-guerin secreting merozoite surface protein 1 (msp-1) induces protection against rodent malaria parasite infection depending on ms ... | 1999 | 10580196 |
| mice immunised with synthetic peptide from n-terminal conserved region of merozoite surface antigen-2 of human malaria parasite plasmodium falciparum can control infection induced by plasmodium yoelii yoelii 265by strain. | synthetic peptides representing conserved msa-2 sequences are being considered as a possible component of a blood stage malaria vaccine. antibody response towards the entire n-terminal conserved region of msa-2 and its constituent b-epitope sntfinna following immunisation of balb/c and c57bl/6 mice with different peptide constructs was assessed by elisa and immunofluorescence antibody test (ifat). co-linear synthesis of sntfinna-epitope in tandem with the entire n-terminal conserved region pepti ... | 1999 | 10580206 |
| a role for cytokines in potentiation of malaria vaccines through immunological modulation of blood stage infection. | malaria is the world's major parasitic disease, for which effective control measures are urgently needed. one of the difficulties hindering successful vaccine design against plasmodium is an incomplete knowledge of antigens eliciting protective immunity, the precise types of immune response for which to aim, and how these can be induced. a greater appreciation of the mechanisms of protective immunity, on the one hand, and of immunopathology, on the other, should provide critical clues to how man ... | 1999 | 10582167 |
| antigenic and sequence diversity at the c-terminus of the merozoite surface protein-1 from rodent malaria isolates, and the binding of protective monoclonal antibodies. | merozoite surface protein-1 (msp-1) is a major candidate in the development of a vaccine against malaria. immunisation with a recombinant fusion protein containing the two plasmodium yoelii msp-1 c-terminal epidermal growth factor-like domains (msp-1(19)) can protect mice against homologous but not heterologous challenge, and therefore, antigenic differences resulting from sequence diversity in msp-1(19) may be crucial in determining the potential of this protein as a vaccine. representative seq ... | 1999 | 10593171 |
| gametocyte-dominant expression of a novel p-type atpase in plasmodium yoelii. | | 1999 | 10593186 |
| plasmodium yoelii: cloning and characterization of the gene encoding for the mitochondrial heat shock protein 60. | heat shock proteins are a highly conserved group of proteins required for the correct folding, transport, and degradation of other proteins in vivo. the hsp70, hsp90, and hsp60 families are among the most widely studied families. hsp60 is found in eubacteria, mitochondria, and chloroplasts, where, in cooperation with hsp10, it participates in protein folding and translocation of proteins to the organelles. we have cloned and characterized the hsp60 gene of plasmodium yoelii (pyhsp60). pyhsp60 is ... | 1999 | 10600443 |
| selection of anopheles dirus for refractoriness and susceptibility to plasmodium yoelii nigeriensis. | two lines of the oriental malaria vector mosquito anopheles dirus species a (diptera: culicidae), one fully refractory and one fully susceptible to plasmodium yoelii nigeriensis (an african rodent malaria parasite), were established after 17 generations of mass selection, followed by single female selection for one or two generations. prior to selection, the stock colony of an. dirus was 17% refractory. both lines of an. dirus produced abundant ookinetes that started to invade the midgut within ... | 1999 | 10608223 |
| characterization of the merozoite surface protein 4/5 gene of plasmodium berghei and plasmodium yoelii. | the genes encoding merozoite surface protein 4/5 (msp4/5) from plasmodium berghei and plasmodium yoelii have been cloned and completely sequenced. comparisons of the predicted protein sequences with those of plasmodium chabaudi msp4/5 and plasmodium falciparum msp4 and msp5 show general structural similarities. all predicted proteins contain hydrophobic signal sequences, potential gpi attachment sequences and a single epidermal growth factor (egf)-like domain at the c-terminus. the amino acid se ... | 2000 | 10613706 |
| docetaxel (taxotere): effectiveness against plasmodium falciparum in vitro and plasmodium yoelii nigeriensis in vivo. | | 1998 | 10622642 |
| azithromycin: antimalarial profile against blood- and sporozoite-induced infections in mice and monkeys. | the spectrum of antimalarial activity of the new macrolide antibiotic azithromycin was evaluated against blood- and sporozoite-induced infections with a chloroquine-resistant strain of plasmodium yoelii nigeriensis (n-67) in swiss mice and with simian parasite plasmodium cynomolgi b in rhesus monkeys. against experimental rodent malaria, a 70 mg/kg/day dose showed curative blood-schizontocidal activity in a four-dose regimen administered orally from day 0 to day 3 or from day 2 to day 5 to mice ... | 2000 | 10631075 |
| blood digestion in the mosquito, anopheles stephensi: the effects of plasmodium yoelii nigeriensis on midgut enzyme activities. | midgut proteases contribute to the success or failure of plasmodium infection of the mosquito. this paper examines the reciprocal effect of plasmodium yoelii nigeriensis on midgut trypsin, chymotrypsin, aminopeptidase and carboxypeptidase in the mosquito anopheles stephensi. the total protein ingested and the rate of protein digestion were unaffected by the parasite, but more protein was ingested at the first than the second bloodmeal. all peptidases were unaffected by the presence of the parasi ... | 1999 | 10633914 |
| malaria multigene families: the price of chronicity. | in this article, georges snounou, william jarra and peter preiser discuss the survival strategy of malaria parasites in the light of a novel mechanism of clonal phenotypic variation recently described for a multigene family of plasmodium yoelii yoelii. the 235 kda rhoptry proteins (py235) encoded by these genes may be involved in the selection of red blood cells for invasion by merozoites. the new mechanism may explain the ability of individual parasites to adapt to natural variations in red blo ... | 2000 | 10637585 |
| mechanisms of artemisinin resistance in the rodent malaria pathogen plasmodium yoelii. | artemisinin and its derivatives are important new antimalarials which are now used widely in southeast asia. clinically relevant artemisinin resistance has not yet been reported but is likely to occur. in order to understand how the malaria parasite might become resistant to this drug, we studied artemisinin resistance in the murine malaria parasite plasmodium yoelii. the artemisinin-resistant strain (art), which is approximately fourfold less sensitive to artemisinin than the sensitive ns strai ... | 2000 | 10639360 |
| liver cd4-cd8- nk1.1+ tcr alpha beta intermediate cells increase during experimental malaria infection and are able to exhibit inhibitory activity against the parasite liver stage in vitro. | experimental infection of c57bl/6 mice by plasmodium yoelii sporozoites induced an increase of cd4-cd8- nk1.1+ tcr alpha beta int cells and a down-regulation of cd4+ nk1.1+ tcr alpha beta int cells in the liver during the acute phase of the infection. these cells showed an activated cd69+, cd122+, cd44high, and cd62lhigh surface phenotype. analysis of the expressed tcrv beta segment repertoire revealed that most of the expanded cd4-cd8- (double-negative) t cells presented a skewed tcrv beta repe ... | 2000 | 10640763 |
| inhibition of the development of the hepatic stages of plasmodium yoelii nigeriensis by antihistaminic agents. | | 1999 | 10656045 |
| interferon-gamma-independent cd8+ t cell-mediated protective anti-malaria immunity elicited by recombinant adenovirus. | recombinant adenovirus, expressing the cs protein of plasmodium yoelii, adpycs, was shown to induce a comparable degree of t cell-mediated protection against malaria as a single dose of irradiated p. yoelii sporozoites, causing inhibition of liver stage development. we now report that differently from sporozoite-induced immunity, interferon (ifn)-gamma does not mediate the protective immunity induced by adpycs, since a similar degree of protection was observed in adpycs immunized mice lacking if ... | 2000 | 10672197 |
| covalent binding of polyethylene glycol to the surface of red blood cells as detected and followed up by cell electrophoresis and rheological methods. | cyanuric chloride activated polyethylene glycol (peg)-5000 was covalently coupled to murine and human red blood cells (pegylated rbc). our purpose was to camouflage rbc receptors, which is necessary for parasite invasion, a process essential to sustain parasitemia. cell electrophoretic mobility analysis (cem) of pegylated rbc distinguished a new population of cells bearing characteristic cem. pegylation of rbc also modified their rheological properties, which were documented by evaluation of cel ... | 2000 | 10675005 |
| plasmodium infection-induced changes in salivary gland proteins of malaria vector anopheles stephensi (diptera:culicidae). | parasitism by plasmodium yoelii yoelii induced 18 polypeptides in the salivary glands of aging malaria vector anopheles stephensi. a polypeptide of low molecular size (30 kda) could generally be induced at all infected stages. on day 5 post blood feeding (pbf), no new polypeptide could be found in the salivary glands. seven polypeptides of low molecular size and 3 of high molecular size could be induced on day 11 pbf, which inducibility coincided with the invasion of the salivary glands by the s ... | 1999 | 10680088 |
| immunogenicity of ty-vlp bearing a cd8(+) t cell epitope of the cs protein of p. yoelii: enhanced memory response by boosting with recombinant vaccinia virus. | we characterized the immunogenicity of the hybrid ty-virus-like carrying the cd8(+) t cell epitope (syvpsaeqi) of the circumsporozoite (cs) protein of plasmodium yoelii (tycs-vlp), a rodent malaria parasite. balb/c mice were immunized with hybrid tycs-vlp, and their cs-specific cd8(+) t cell response was quantitatively evaluated with the elispot assay, based on the enumeration of epitope specific gamma-interferon secreting cd8(+) t cell. a single immunization with the tycs-vlp by a variety of ro ... | 2000 | 10699335 |
| linkage of exogenous t-cell epitopes to the 19-kilodalton region of plasmodium yoelii merozoite surface protein 1 (msp1(19)) can enhance protective immunity against malaria and modulate the immunoglobulin subclass response to msp1(19). | the degree of protection against plasmodium yoelii asexual blood stages induced by immunization of mice with the 19-kda region of merozoite surface protein 1 (msp1(19)) is h-2 dependent. as a strategy to improve the protection, mouse strains with disparate h-2 haplotypes were immunized with glutathione s-transferase (gst)-msp1(19) proteins including either a universal t-cell epitope from tetanus toxin (p2) or an i-a(k)-restricted t-cell epitope (p8) from plasmodium falciparum pf332. in h-2(k) mi ... | 2000 | 10722607 |
| gammadelta t cells are a component of early immunity against preerythrocytic malaria parasites. | we tested the hypothesis that gammadelta t cells are a component of an early immune response directed against preerythrocytic malaria parasites that are required for the induction of an effector alphabeta t-cell immune response generated by irradiated-sporozoite (irr-spz) immunization. gammadelta t-cell-deficient (tcrdelta(-/-)) mice on a c57bl/6 background were challenged with plasmodium yoelii (17xnl strain) sporozoites, and then liver parasite burden was measured at 42 h postchallenge. liver ... | 2000 | 10722623 |
| status of hepatic oxidative stress and antioxidant defense systems during chloroquine treatment of plasmodium yoelii nigeriensis infected mice. | plasmodium yoelii nigeriensis (p. y. nigeriensis) produces lethal malaria infection in swiss albino mice. reactive oxygen species (ros) such as superoxide anion, hydrogen peroxide have been implicated in the pathogenesis of malaria. | 1999 | 10757052 |
| immunization with parasite-derived apical membrane antigen 1 or passive immunization with a specific monoclonal antibody protects balb/c mice against lethal plasmodium yoelii yoelii ym blood-stage infection. | we have purified apical merozoite antigen 1 (ama-1) from extracts of red blood cells infected with the rodent malaria parasite plasmodium yoelii yoelii ym. when used to immunize mice, the protein induced a strong protective response against a challenge with the parasite. monoclonal antibodies specific for p. yoelii yoelii ama-1 were prepared, and one was very effective against the parasite on passive immunization. a second protein that appears to be located in the apical rhoptry organelles and a ... | 2000 | 10768987 |
| immunoglobulin g3 antibodies specific for the 19-kilodalton carboxyl-terminal fragment of plasmodium yoelii merozoite surface protein 1 transfer protection to mice deficient in fc-gammari receptors. | merozoite surface protein 1 (msp-1(19)) is a leading malaria vaccine candidate. specific antibodies contribute to immunity; binding to macrophages is believed to represent the main action of malaria antibodies. we show that an msp-1(19)-specific immunoglobulin g3 (igg3) monoclonal antibody can passively transfer protection to mice deficient in the alpha chain of fc-gammari whose macrophages cannot bind igg3. | 2000 | 10769007 |
| plasmodium yoelii: identification of a gene encoding a putative adp-ribosylation factor-1 gtpase-activating protein, pyag1. | the pyag1 gene, identified by the screening of a plasmodium yoelii genomic dna library with a rhoptry-specific mab, encodes a protein with a zinc finger structure immediately followed by the consensus sequence of the arf gap catalytic site. the serum of mice immunized with the recombinant protein recognized specifically the rhoptries of the late infected erythrocytic stages. blast analysis using the genbank database gave the highest scores with four proteins presenting an arf1 gap activity. if p ... | 2000 | 10800192 |
| studies on hepatic mitochondrial cytochrome p-450 during plasmodium yoelii infection and pyrimethamine treatment in mice. | hepatic mitochondrial cytochrome p-450 and b(5) activities were significantly depressed, whereas heme and hemozoin were increased during plasmodium yoelii infection. type ii, aniline-hcl binding efficacy and polyacrylamide gel electrophoretic profile also depicted impairment of cytochrome p-450 during infection. however, the above alterations were more pronounced in the infected hepatic mitochondria, compared to microsomes. oral treatment of pyrimethamine (10 mg/kg body weightx4 days) to p. yoel ... | 2000 | 10805988 |
| a subdominant cd8(+) cytotoxic t lymphocyte (ctl) epitope from the plasmodium yoelii circumsporozoite protein induces ctls that eliminate infected hepatocytes from culture. | previous studies indicated that the plasmodium yoelii circumsporozoite protein (pycsp) 57-70 region elicits t cells capable of eliminating infected hepatocytes in vitro. herein, we report that the pycsp58-67 sequence contains an h-2(d) binding motif, which binds purified k(d) molecules in vitro with low affinity (3, 267 nm) and encodes an h-2(d)-restricted cytotoxic t lymphocyte (ctl) epitope. immunization of balb/c mice with three doses of a multiple antigen peptide (map) construct containing f ... | 2000 | 10816491 |
| antibodies against thrombospondin-related anonymous protein do not inhibit plasmodium sporozoite infectivity in vivo. | thrombospondin-related anonymous protein (trap), a candidate malaria vaccine antigen, is required for plasmodium sporozoite gliding motility and cell invasion. for the first time, the ability of antibodies against trap to inhibit sporozoite infectivity in vivo is evaluated in detail. trap contains an a-domain, a well-characterized adhesive motif found in integrins. we modeled here a three-dimensional structure of the trap a-domain of plasmodium yoelii and located regions surrounding the midas (m ... | 2000 | 10816526 |
| improving protective immunity induced by dna-based immunization: priming with antigen and gm-csf-encoding plasmid dna and boosting with antigen-expressing recombinant poxvirus. | intramuscular immunization with a naked dna plasmid expressing the plasmodium yoelii circumsporozoite protein (ppycsp) protects mice against challenge with p. yoelii sporozoites. this protection can be improved either by coadministration of a plasmid expressing murine gm-csf (pgmcsf) or by boosting with recombinant poxvirus expressing the pycsp. we now report that combining these two strategies, by first mixing the priming dose of ppycsp with pgmcsf and then boosting with recombinant virus, can ... | 2000 | 10820272 |
| plasmodium yoelii nigeriensis (mdr)-efficacy of oral pyronaridine against multidrug-resistant malaria in swiss mice. | a multidrug-resistant strain of plasmodium yoelii nigeriensis (mdr) showing a wide spectrum of resistance to chloroquine, amodiaquine, mepacrine, mefloquine, halofantrine, quinine, and quinidine was used in this study for in vivo evaluation of the blood schizontocidal activity of pyronaridine, a topoisomerase ii inhibitor, in swiss mice. the parasite produces 100% lethal infection in mice. the drug was administered orally once a day from day 0 onward. the initial studies showed that low doses of ... | 2000 | 10831384 |
| spatial and temporal dynamics of the secretory pathway during differentiation of the plasmodium yoelii schizont. | a specialized complex of apical organelles facilitates plasmodium merozoite invasion into the erythrocyte. even though the apical organelles are crucial to the invasion process, relatively little is known about how they function or their biosynthesis during asexual replication. maebl is an erythrocyte binding protein located in the rhoptries and on the surface of mature merozoites and is expressed at the beginning of schizogony before the first nuclear division. therefore, we have characterized ... | 2000 | 10838220 |
| plasmodium vivax reticulocyte binding protein-2 (pvrbp-2) shares structural features with pvrbp-1 and the plasmodium yoelii 235 kda rhoptry protein family. | | 2000 | 10838229 |
| sequence analysis of the rhop-3 gene of plasmodium yoelii. | the 110 kda/rhop-3 rhoptry protein of plasmodium falciparum is non-covalently associated with two other proteins, the 140 kda rhop-1 and the 130 kda rhop-2. cdnas encoding rhop-3 from plasmodium yoelii were isolated using rhoptry-specific antisera from plasmodium falciparum, p. yoelii, and plasmodium chabaudi. the cdnas encoded peptides with partial homology to the c-terminal region (residues 541-861) of p. falciparum rhop-3. core regions of homology to the p. falciparum gene will be useful in d ... | 2000 | 10847350 |
| antibodies against ribosomal phosphoprotein p0 of plasmodium falciparum protect mice against challenge with plasmodium yoelii. | antibodies against the plasmodium falciparum p0 ribosomal phosphoprotein (pfp0) have been detected exclusively but extensively in malaria-immune persons. polyclonal rabbit and mice sera were raised against two recombinant polypeptides of p. falciparum p0 protein, pfp0n and pfp0c, covering amino acids 17 to 61 and the remaining amino acids 61 to 316, respectively. sera against both these domains detected a 35-kda protein from plasmodium yoelii subsp. yoelii, a rodent malarial parasite, and staine ... | 2000 | 10858250 |
| immune responses mediating survival of naive balb/c mice experimentally infected with lethal rodent malaria parasite, plasmodium yoelii nigeriensis. | the rodent malaria parasite, plasmodium yoelii nigeriensis is known to cause fatal malaria infections in balb/c mice. however, we found that nearly 5% of inbred balb/c mice could overcome primary infections initiated with lethal inoculum of p. y. nigeriensis asexual blood-stages, without any experimental intervention. these 'survivor' mice developed peak parasitemia levels of about 5% and successfully resolved their infections in about two weeks time; infected blood collected during the descendi ... | 2000 | 10865192 |
| [assessment of malaria dna vaccines in mice and monkeys]. | cholera toxin b subunit is a good carrier protein and an effective adjuvant which can boost both cellular and humoral immunity. dna fragments encoding b cell, th cell and ctl epitopes of p. falciparum cs, msa-1, msa-2 and resa antigens were cloned down-2 stream of cholera toxin b subunit gene in the same reading frame. high titer of anti-malaria epitopes antibodies and strong cellular immunogenicity were elicited after balb/c mice were immunized three times with 100 micrograms recombinant plasmi ... | 2000 | 10887674 |
| alpha -galactosylceramide-activated valpha 14 natural killer t cells mediate protection against murine malaria. | natural killer t (nkt) cells are a unique population of lymphocytes that coexpress a semiinvariant t cell and natural killer cell receptors, which are particularly abundant in the liver. to investigate the possible effect of these cells on the development of the liver stages of malaria parasites, a glycolipid, alpha-galactosylceramide (alpha-galcer), known to selectively activate valpha14 nkt cells in the context of cd1d molecules, was administered to sporozoite-inoculated mice. the administrati ... | 2000 | 10900007 |
| effects of in vivo administration of anti-il-10 or anti-ifn-gamma monoclonal antibody on the host defense mechanism against plasmodium yoelii yoelii infection. | our previous reports indicated that c57bl/6 mice infected with a lethal variant of plasmodium yoelii 17x (p. yoelii 17xl) produced high levels of interleukin 10 (il-10) and interferon-gamma (ifn-gamma) while mice infected with the nonlethal variant of the parasite did not produce detectable levels of il-10. in the present study, the involvement of il-10 and ifn-gamma in exacerbation or regulation of blood-stage malaria was investigated by using the lethal variant of p. yoelii 17xl and monoclonal ... | 2000 | 10907683 |
| reversal of type 2 diabetes in mice by products of malaria parasites: i. effect of inactivated parasites. | c57bl/ksj-db/db and c57bl/ksj-ob/ob mice are good models for studies on human obesity and type 2 diabetes. we have previously shown that infection with blood-stage malaria or injection of extracts from malaria-parasitized red blood cells induces hypoglycemia in normal mice and normalizes hyperglycemia in mice made moderately diabetic by streptozotocin. in the present study, we show that a single intravenous (iv) injection of formalin-fixed plasmodium yoelii ym (ffym) preparation decreases blood ... | 2000 | 10910007 |
| two plasmodium falciparum genes express merozoite proteins that are related to plasmodium vivax and plasmodium yoelii adhesive proteins involved in host cell selection and invasion. | two related plasmodium falciparum genes and their encoded proteins have been identified by comparative analyses with plasmodium vivax reticulocyte binding protein 2 (pvrbp-2). the p. falciparum genes have a structure which suggests that they may be the result of an evolutionary duplication event, as they share more than 8 kb of closely related nucleotide sequence but then have quite divergent unique 3' ends. between these shared and unique regions is a complex set of repeats, the nature and numb ... | 2000 | 10920203 |
| recombinant attenuated toxoplasma gondii expressing the plasmodium yoelii circumsporozoite protein provides highly effective priming for cd8+ t cell-dependent protective immunity against malaria. | the protozoan parasite toxoplasma gondii elicits strong cell-mediated immunity against itself as well as nonspecific resistance against other pathogens and tumors. for this reason, we asked whether recombinant toxoplasma could be utilized as an effective vaccine vehicle for inducing immunity against heterologous microbial infections. the circumsporozoite protein (pycsp) of plasmodium yoelii was engineered into a t. gondii temperature-sensitive strain (ts-4), a mutant that induces complete protec ... | 2000 | 10925293 |
| studies on erythrocytic methemoglobin reductase systems in plasmodium yoelii nigeriensis infected mice. | the methemoglobin reductase system plays a vital role in maintaining the equilibrium between hemoglobin and methemoglobin in blood. exposure of red blood cells to oxidative stress (pathological/physiological) causes an impairment in this equilibrium. | 2000 | 10945172 |
| host-virus interactions during malaria infection in hepatitis b virus transgenic mice. | we have previously shown that hepatitis b virus (hbv) replication is abolished in the liver of hbv transgenic mice by inflammatory cytokines induced by hbv-specific cytotoxic t cells and during unrelated viral infections of the liver. we now report that intrahepatic hbv replication is also inhibited in mice infected by the malaria species plasmodium yoelii 17x nl. p. yoelii infection triggers an intrahepatic inflammatory response characterized by the influx of natural killer cells, macrophages, ... | 2000 | 10952722 |
| plasmodium yoelii: effects of red blood cell modification and antibodies on the binding characteristics of the 235-kda rhoptry protein. | the 235-kda rhoptry protein of the rodent malaria parasite plasmodium yoelii yoelii was shown to bind to the surface of mouse red blood cells in a calcium-independent process, using a erythrocyte-binding assay. this binding is affected by modification of the surface of the red blood cells by enzymatic treatment. chymotrypsin and trypsin but not neuraminidase treatment of the erythrocytes significantly reduced the binding of the 235-kda proteins. the binding of an unrelated 135-kda protein was ab ... | 2000 | 10964646 |