Publications

quantification of sporozoite invasion, migration, and development by microscopy and flow cytometry.	there is an important role for in vitro assays to better understand the initial steps of malaria infection. in this section, we describe both microscopy-based and flow cytometry-based sporozoite invasion, migration and development assays with the rodent malaria parasites, plasmodium berghei and plasmodium yoelii, and the human malaria parasite, plasmodium falciparum.	0	22990793
the utility of plasmodium berghei as a rodent model for anti-merozoite malaria vaccine assessment.	rodent malaria species plasmodium yoelii and p. chabaudi have been widely used to validate vaccine approaches targeting blood-stage merozoite antigens. however, increasing data suggest the p. berghei rodent malaria may be able to circumvent vaccine-induced anti-merozoite responses. here we confirm a failure to protect against p. berghei, despite successful antibody induction against leading merozoite antigens using protein-in-adjuvant or viral vectored vaccine delivery. no subunit vaccine approa ...	0	23609325
hiv nonnucleoside reverse transcriptase inhibitors and trimethoprim-sulfamethoxazole inhibit plasmodium liver stages.	although nonnucleoside reverse transcriptase inhibitors (nnrtis) are usually part of first-line treatment regimens for human immunodeficiency virus (hiv), their activity on plasmodium liver stages remains unexplored. additionally, trimethoprim-sulfamethoxazole (tmp-smx), used for opportunistic infection prophylaxis in hiv-exposed infants and hiv-infected patients, reduces clinical episodes of malaria; however, tmp-smx effect on plasmodium liver stages requires further study.	0	23125449
[blood relapses and modifications of the pre-erythrocytic shizonts of plasmodium yoelii using ethionine].	injections of dl-ethionine during the preerythrocytic period of plasmodium yoeli in thammomys were followed by: 1. a delayed prepatent period; 2. a relapsing parasitaemia with alternatively positive and negative blood at subinoculation of clean mice; 3. a peculiar morphology of the exoerythrocytic schizonts which remain small with a scanty cytoplasm and very few large nuclei. although the authors consider the origin of the relapses to be the rupture of delayed hepatic schizonts under the influen ...	1975	807419
the chemotherapy of rodent malaria, xxiii causal prophylaxis, part ii: practical experience with plasmodium yoelii nigeriensis in drug screening.	data are presented on the causal prophylactic action of about 100 compounds of various types against plasmodium yoelii nigeriensis n67 in mice. examples are given to show how action against pre-erythrocytic schizonts may be differentiated from action on emerging erythrocytic stages. in a series of 35 8-aminoquinolines, all but 10 showed definite causal prophylactic activity at tolerated doses. the data permit the compounds to be ranked in order of activity, and many are shown to be more active i ...	1975	1098590
cytology and kinetics of microgametogenesis and fertilization in plasmodium yoelii nigeriensis.	the sexual development of the microgametocyte of plasmodium yoelii nigeriensis may be subdivided into microgametogenesis which includes exflagellation, dispersal of the gametes and fertilization. under our experimental conditions microgametogenesis takes about 8-15 min at 20 degrees c, the duration of this period being inversely related to temperature. exflagellation takes less than 1 min, subsequent dispersal of gametes may continue for 40 min. we find that exflagellation is totally inhibited i ...	1975	1118188
new observations on the malaria parasites of rodents of the central african republic - plasmodium vinckei petteri subsp. nov. and plasmodium chabaudi landau, 1965.	the morphology and enzyme forms of malaria parasites isolated from 50 wild caught specimens of thamnomys rutilans from the central african republic have been studied and three distinct species of plasmodium identified. one species has been confirmed as plasmodium yoelii yoelii. morphological features of both the remaining species correspond to those given by landau (1965) in her original description of plasmodium chabaudi. for one of these species the name p. chabaudi has been retained; the othe ...	1975	1155987
a genetic investigation of virulence in a rodent malaria parasite.	the genetic basis of virulence in a line (ym) of plasmodium yoelii yoelii was investigated in a cross with a mild line (a/c). the blood forms of the virulent line developed extensively in mature erythrocytes of mice, causing death of the host within 7 days; infections with the mild line were normally restricted to reticulocytes, infected animals recovering after three weeks. lines ym and a/c differed additionally in enzyme and drug-sensitivity markers. studies on infections established from each ...	1976	1264490
schizont-infected cell enrichment in rodent malaria.	mouse erythrocytes parasitized with plasmodium berghei or plasmodium yoelii were separated by ultracentrifugation using preformed isodensity gradients of the discontinuous type. three fractions were obtained following centrifugation, the upper of which contained greater than 90% of all schizont-infected cells added to the gradient. the gradient material, stractan ii, is an arabinogalactan polysaccharide and appears to yield results similar to those available using gradients of bovine serum album ...	1976	789847
influence of rodent malaria on the course of leishmania enriettii infection of hamsters.	plasmodium yoelii infection was established in hamsters, and the effect of this type of malaria on concurrent leishmania enriettii infection was examined. it was found that the course of the l. enriettii infection was affected by p. yoelii and that this effect depended on the relative timing of the two infections. a chronic malarial infection with plasmodium berghei was also established in hamsters, and this was found to affect the course of a concurrent l. enriettii infection in a similar manne ...	1976	786886
gametogenesis and fertilization in plasmodium yoelii nigeriensis: a transmission electron microscope study.		1976	4810
plasmodium yoelii and plasmodium vinckei: the effects of nonspecific immunostimulation on murine malaria.		1977	330190
inhibition of the immune response to whooping cough and tetanus vaccines by malaria infection, and the effect of pertussis adjuvant.	plasmodium yoelii infection of mice depressed their capacity to build up humoral immune response to diphteria vaccine and protective immunity against tetanus toxin. this immunodepression was overcome by freund's complete adjuvant or killed pertussis bacilli (whooping cough vaccine). these results suggest that vaccines should be given in association in malaria endemic area.	1977	869103
antibody response in vitro of spleen cells from plasmodium yoelii-infected mice.	the primary antibody response to sheep erythrocytes and dinitrophenylated ficoll of spleen cells from mice infected with plasmodium yoelii was studied in vitro. the response to sheep erythrocytes was enhanced between 2 and 4 days after infection and depressed at later intervals. cell fractionation experiments carried out at the time of immunosuppression indicated a defect of macrophage function. at the same time the response to dinitrophenylated ficoll was normal.	1977	324908
immunosuppression in murine malaria. i. response to type iii pneumococcal polysaccharide.	acute plasmodium yoelii yoelii and chronic plasmodium berghei malaria infections of cba mice were accompanied by a reduced capacity to give an antibody response to type iii pneumococcal polysaccharide (siii). the depression of response initiated by acute malaria persisted for several weeks after recovery from clinical infection. during chronic infection, and at the peak of acute parasitaemia, virtually no response to siii was detected. a substance which crossreacted serologically with siii was f ...	1977	67996
immunosuppression in murine malaria. ii. the primary response to bovine serum albumin.	the primary antibody response to alumadsorbed bovine serum albumin was depressed in cba mice infected with plasmodium yoelii yoelii. responses initiated within approximately 3 weeks of this malaria infection were reduced in quantity, but not in avidity. responses initated later were normal. a depressed primary response was also seen in infected compared to control splenectomized mice; this was accompanied by impaired priming for a secondary response.	1977	608688
the action of metabolic inhibitors on microgametogenesis in plasmodium yoelii nigeriensis.	mature gametocytes of plasmodium yoelii nigeriensis were incubated in vitro with a variety of antibiotics whose activities were directed against dna, rna, protein and microtubule assembly. following incubation for periods between 5 and 90 min, exflagellation was induced and the degree of inhibition produced by each drug was assayed microscopically. the results obtained show that de novo synthesis of axonemes and proteins is essential to the events of microgametogenesis. the inhibitory effect of ...	1977	919692
cytofluorograf detection of plasmodium yoelii, trypanosoma gambiense, and trypanosoma equiperdum by laser excited fluorescence of stained rodent blood.	samples of rat blood infected with plasmodium yoelii (3% parasitized erythrocytes), trypanosoma gambiense, or trypanosoma equiperdum (greater than 50 trypanosomes per microscope field at 400 x) were fixed with 0.5% glutaraldehyde in phosphate buffered saline, then stained with acridine orange (ao) at 10(-4), 10(-5), or 10(-6) m for 0 to 15 min at 5 c or 25 c and/or ethidium bromide (eb) at 0.05 mg/ml for 20 min at 25 c. stained cells were analyzed with a laser cytofluorograf (bio/physics systems ...	1977	886402
plasmodium yoelii: an inbred model for protective immunization against malaria in balb/c mice.		1977	849768
protection of mice against plasmodium and babesia infections: attempts to raise host-protective sera.	in an attempt to generate large numbers of mice resistant to plasmodium berghei and babesia rodhaini to be used as donors of antibody-secreting cells for hybridoma production, various methods of inducing resistance to repeated challenge with infected blood cells have been explored. although results of independent experiments varied markedly, prior injection of cba/m mice with bcg, and prior infection of balb/c mice with plasmodium yoelii, were found to be manipulations capable of inducing resist ...	1978	375903
exacerbation of murine malaria by concurrent infection with lactic dehydrogenase-elevating virus.	the simultaneous infection of mice with lactic dehydrogenase-elevating virus (ldv) and plasmodium yoelii resulted in an exacerbated attack of malaria. peak parasitaemia was higher and the patent infection more prolonged in doubly infected mice. the results indicate that contamination with ldv must be considered when a change in parasite virulence is observed, particularly when the parasite is maintained by blood passage in mice.	1978	719954
splenomegaly, enhanced phagocytosis, and anemia are thymus-dependent responses to malaria.	immunologically competent mice and mice with defined immunological deficiencies were infected with plasmodium yoelii. splenomegaly, enhanced phagocytosis, and anemia were most marked in infected mice having intact thymic tissue. whereas the spleens of infected nude mice increased minimally in size, the relative blood hemoglobin levels and the rates of carbon clearance in these mice were similar to those of noninfected, immunologically intact mice. thymus-reconstituted nude mice and b-cell-defici ...	1978	669820
chronic malarial infection of mice: a comparison of single and multiple infections with plasmodium berghei following p. yoelii.	chronic malarial infection was induced in two groups of balb/c mice by injection of plasmodium yoelii followed by either one or repeated injections of p. berghei. both groups showed a continuing but fluctuating splenomegaly, and a considerably increased reticulocyte count which also varied regularly, over a period of six months. during this time many mice had a very low grade parasitaemia demonstrable by subinoculation of blood into uninfected recipients. mice infected with p. yoelii alone did n ...	1978	366816
immunity to plasmodium yoelii and babesia microti: modulation by the cba/n x-chromosome.	cba/n mice carry an x-linked recessive defect expressed in cells of the b cell lineage. the major deficiency in these mice is an almost complete inability to respond to certain thymus-independent antigens, such as pneumococcal polysaccharide type iii (s iii). we have examined the responses of mice carrying the cba/n x-chromosome to the malaria parasite plasmodium yoelii and the piroplasm babesia microti. we have found that the duration and severity of these infections is increased in mice carryi ...	1979	317444
lethal plasmodium yoelii malaria: the role of macrophages in normal and immunized mice.	mice were injected with silica or corynebacterium parvum, which, respectively, inhibit and stimulate macrophages in vivo, in an attempt to study the role of macrophages in lethal plasmodium yoelii infection and in mice protected by immunization. in the normal infection, macrophages were able to control parasitaemia for up to 1 week, whereas in immunized mice they appeared to inhibit the sterilizing immune response. a model is proposed in which this dual role of activated macrophages may account ...	1979	317443
influence of the sex-linked defect in cba/n mice on autoimmune responses to isologous erythrocytes. ability to overcome the defect with age.	normal mice spontaneously develop plaque-forming cells (pfc) specific for antigens on modified self erythrocytes (bromelain-treated mouse erythrocytes [brmrbc] antigens). our study demonstrates that the sex-linked defect that results in the inability of cba/n mice to respond to several t-independent antigens (ti-2 antigens) also regulates the autoantibody response to brmrbc antigens. thus, in cba/n homozygous mice and male f1 offspring of cba/n-mothered crosses, e.g., (cba/n x nzb)f1 males, such ...	1979	315995
t-cell immunity to malaria in the b-cell deficient mouse.	some b-cell deficient mice drug-rescued with clindamycin hcl from otherwise lethal infections with plasmodium yoelii resisted subsequent challenge with the same parasite despite the fact that they lacked detectable antibody to plasmodia. parasitemias remained patent but at low levels (less than or equal to 5%) in these mice for prolonged periods of time, suggesting that some t-cell function independent of antibody formation can in part mediate immunity to malaria.	1979	312025
development and suppression of a population of late-adhering macrophages in mouse malaria.	changes in phagocytic and adherent cell numbers were compared during the course of infections of mice with plasmodium yoelii (py) and p. berghei (pb) and in vaccinated mice challenged with homologous parasites. nucleated cells in the spleen increased in number in py-infected mice and were maximal at the time of recovery. the number of phagocytic cells increased in parallel, as did the number of blood leucocytes. rates of increase were accelerated in vaccinated mice. changes in pb-infected mice r ...	1979	233150
biochemistry of intraerythrocytic parasites. i. identification of enzymes of parasite origin by starch-gel electrophoresis.	enzymes of parasite origin were identified by starch-gel electrophoresis. the species of parasite studied were plasmodium berghei, plasmodium yoelii nigeriensis, babesia rodhaini and anthemosoma garnhami. lactate dehydrogenase, glucose phosphate isomerase and (nadp) glutamate dehydrogenase were detected in all species; phosphogluconate dehydrogenase was detected in both plasmodium species but malate dehydrogenase only in p. y. nigeriensis. glucose-6-phosphate dehydrogenase, alanine aminotransfer ...	1979	386967
biochemistry of intraerythrocytic parasites. ii. comparative studies in carbohydrate metabolism.	comparative studies were carried out on the glucose catabolism of mouse erythrocytes infected with plasmodium berghei, plasmodium yoelii, babesia rodhaini, babesia microti and anthemosoma garnhami, as well as on uninfected erythrocytes and reticulocytes. the results showed that there was little qualitative difference between the glucose utilization and lactate production of the parasites although quantitative differences between malaria parasites and piroplasms were observed. the rate of glucose ...	1979	386968
host defenses in murine malaria: evaluation of the mechanisms of immunity to plasmodium yoelii infection.	the immune response of random-bred mice to infection with a relatively avirulent strain of plasmodium yoelii was measured in terms of parasitemia, splenomegaly, immediate and delayed hypersensitivity to a p. yoelii antigen preparation, resistance to challenge with a virulent variant of p. yoelii, and nonspecific resistance to l. monocytogenes. avirulent p. yoelii produced a self limiting infection which resolved in 21 days. peak parasitemia and splenomegaly were observed at 14 days, and infected ...	1979	422246
[malaria plasmodia in the mouse. parasitization of mature and immature erythrocytes by plasmodium berghei, plasmodium yoelii and plasmodium chabaudi (author's transl)].	plasmodium berghei parasites (strain k173) in mice with developing immunity changed to a variant type with increased resistance against antibodies and enhanced invasion of mature erythrocytes; on passages in normal mice this variant type retransformed to the normal type (kretschmar 1964). on detailed study, parasites of the variant type showed a markedly decreased predilection for polychromatophilic erythrocytes, leading to slowed multiplication during prepatency, increased invasion of mature er ...	1979	384629
[new data on the biology of gametocytes of plasmodium yoelii yoelli gathered from morphological characteristics indicating their age].	a morphological study has been made of the gametocytes of p. yoelii (a parasite of rodents belonging to the "vivax" group). the authors distinguish 4 types chronologically ordered. moreover, morphology enables one to predict their infectivity. the morphological analysis represents a tool leading to new data on the biology of gametocytes: loss of infectivity as soon as the parasitaemia becomes high; infectivity restricted to the young stages; concentration of young stages in the blood ingested by ...	1979	108020
ia antigens in serum during different murine infections.	there exists in the mouse a family of i-region-controlled (ia) antigens which carry carbohydrate-defined determinants. these antigens appear in serum as glycolipids and seem to be actively secreted by antigen-activated t-cells. this paper describes the ability of selected viral, bacterial, and protozoal infections of mice to markedly alter the serum levels of these ia antigens. all the infectious agents examined induced substantial augmentation or suppression of serum ia concentrations or both. ...	1979	94905
[study of gametocytes from the plasmodium "vivax" group: morphology, development in anopheles and infectivity of plasmodium yoelii microgametocytes].	the study of the gametocytes of plasmodium yoelii enabled the differentiation of 4 morphological types: o, i, ii and iii (in a chronological order) and amongst each of these types the differentiation of healthy and altered gametocytes. these morphological data represent a tool for investigations on the biology of the gametocytes of the "vivax" group. preliminary experiments bring informations on the evolution of gametocytes and the mechanisms of their infectivity. 1--in experimentaly infected wh ...	1979	539716
experimental malaria in the cba/n mouse.	cba/n mice carry an x-linked, recessive gene, which results in the absence of a b cell subset, and is expressed primarily as an inability to respond to a certain class of thymus-independent antigens. we have examined the responses of these mice to the malaria parasite plasmodium yoelii and found that primary infections induced by this parasite are more severe and last longer in mice with x-linked defect than in normal controls. the decreased resistance of the defective mice is associated with a ...	1979	387872
immunosuppression in murine malaria. iv. the secondary response to bovine serum albumin.	the anamnestic antibody response of cba mice to bovine serum albumin was characterized by a rapid production of high-avidity antibody. after 3 weeks both the total amount of antibody and its avidity declined but still remained above those seen in the primary response for at least 6 weeks. the effects of acute plasmodium berghei and plasmodium yoelii yoelii infections upon the induction and the expression of this anamnestic response were studied. mice infected with these malaria parasites respond ...	1979	399334
defective resistance to plasmodium yoelii in cba/n mice.	the role of b lymphocytes in resistance to malaria was studied in defective and normal f1 mice derived from cba/n mice, a strain with an x-linked b cell defect. when infected with normally nonlethal plasmodium yoelii, immune defective f1 male mice had higher parasitemias and more prolonged infections than normal f1 mice, as well as a 50% mortality rate. before infection the plasma levels of igm and igg were lower in defective f1 males than normal f1 mice. the polyclonal igm and igg responses of ...	1979	448143
plasmodium yoelii and plasmodium berghei: isolation of infected erythrocytes from blood by colloidal silica gradient centrifugation.		1980	6248355
[new data on the circadian cycle of plasmodium. preliminary note].	a frozen strain of plasmodium yoelii nigeriensis is inoculated at 4 pm, midnight and 9 am onto inbred mice. in all instances young gametocytes (type 0) appear in the blood only between 10 am and 6 pm. although the erythrocytic schizogony occurs regularly during the whole circadian period, the latency increases progressively when the infective subinoculations are made at midnight, 4 pm and 9 am. possibly, the infective merozoite can only enter the red blood cell around midnight.	1980	6784953
[experimental production of variants with lowered preference for polychromatophilic erythrocytes in plasmodium yoelii (author's transl)].	after 25 massive passages of a plasmodium yoelii-population (strain 17x) in the phase of high parasitization of mature erythrocytes, parasites with markedly lowered preference for immature erythrocytes could be isolated. of 3 isolates in 3 independent experiments, one showed a distinctly lower preference than the other two. with very high infecting doses, the isolates caused in most mice high parasitization of mature erythrocytes and death. the original strain had been kept in mice by passage of ...	1980	7414678
two distinct types of non-specific immunosuppression in murine malaria.	a comparative study of non-specific immunosuppression by malaria has been carried out in five situations: in both unvaccinated and vaccinated mice infected with the lethal plasmodium yoelii or the lethal plasmodium berghei, and in the unvaccinated non-lethal p. yoelii infection. spleen cells showed a suppressive effect on the normal blastogenic response to mitogens. this suppression was strongest in the mice vaccinated before infection with the lethal p. yoelii and in those infected with non-let ...	1980	7011609
plasmodium yoelii: the thymus-dependent lymphocyte in mice immunodepressed by malaria.		1980	6967825
host defenses in murine malaria: immunological characteristics of a protracted state of immunity to plasmodium yoelii.	random-bred icr mice recovered from infection with avirulent plasmodium yoelii were challenged at various later times with virulent p. yoelii or with another species of plasmodium, p. berghei, to characterize the immunological nature of the long-term state of immunity generated in response to the avirulent infection. it was found that recovered mice resisted lethal challenge with virulent p. yoelii through at least 416 days after primary infection. however, the quality of this immunity changed a ...	1980	6987179
protective monoclonal antibodies recognising stage-specific merozoite antigens of a rodent malaria parasite.	immunity to malaria is mediated, at least in part, by antibody. resistance to infection has been passively transferred with immune serum or its immunoglobulin fraction in human, simian and rodent malaria. however, because of the structural and antigenic complexity of the malaria parasites, it has proved difficult to identify and characterise those parasite antigens against which protective antibody is directed. we have produced several hybrid cell lines secreting monoclonal antibodies against th ...	1980	7360274
the chemotherapy of rodent malaria, xxxii. the influence of p-aminobenzoic acid on the transmission of plasmodium yoelii and p. berghei by anopheles stephensi.	more oocysts of plasmodium yoelii developed in anopheles stephensi if the mosquitoes received a supplement of p-aminobenzoic acid (paba) in their diet prior to their taking an infective blood meal, than in unsupplemented control insects. the optimum concentration was 0.05% paba in 10% sucrose. this effect was not observed if the blood meal was taken prior to feeding with paba. similarly, paba administered to gametocyte-carrying mice increased the numbers of oocysts developing in mosquitoes fed o ...	1980	6994664
variable expression of virulence in the rodent malaria parasite plasmodium yoelii yoelii.	the expression of the virulence character in the virulent line (ym) of plasmodium yoelii yoelii was investigated. the level of virulence was measured by counting the parasitaemia of the mature red blood cells. several sub-clones were isolated from the virulent line ym and each was tested for its level of virulence. out of 10 sub-clones 1 showed a marked decrease in virulence. however, transmission of this sub-clone through mosquitoes fully restored its virulence. a clone isolated from the progen ...	1980	7422362
radioimmunoassay for detecting antibodies against murine malarial parasite antigens: monoclonal antibodies recognizing plasmodium yoelii antigens.	a solid-phase radioimmunoassay (spria) in microtiter wells was established for detecting antibodies against plasmodium yoelii ag. the spria was found 1) to require as little as 5 micrograms of crude parasite ag per well, 2) to be able to detect 0.5 ng of monoclonal ab, and 3) to be 10(4) times more sensitive than the indirect fluorescent ab staining technique. in a modification of the above assay using intact rbc as an ag, hyperimmune serum showed significant binding to the surface of erythrocyt ...	1980	7430638
the role of the liver in immunity to blood-stage murine malaria.	mice vaccinated with fixed parasitized red blood cells and bordetella pertussis can clear an otherwise lethal plasmodium yoelii infection in 7 days; this protection is abolished by splenectomy before vaccination. most mice splenectomized following vaccination were able to clear their infections, although their recovery was delayed. when labelled parasitized red cells were injected into mice during an infection, splenic uptake fell from day 3 onwards while uptake by the liver increased. lymphocyt ...	1980	7439934
characterization of surface proteins and glycoproteins on red blood cells from mice infected with haemosporidia: plasmodium yoelii infections of balb/c mice.	lactoperoxidase-catalysed radio-iodination was used to compare the surface proteins on red cells from plasmodium yoelii-infected with normal balb/c mice. the profile of radio-iodinated proteins separated by sds-polyacrylamide gel electrophoresis was different for infected blood of similar parasitaemia from mice inoculated with different doses of the parasite. inoculation with different doses of the parasite. inoculation with the lower dose resulted in the appearance of a major radio-iodinated pr ...	1980	7443294
malaria in asplenic mice: effects of splenectomy, congenital asplenia, and splenic reconstitution on the course of infection.	in investigations on the role of the spleen in host defense against malaria, we studied the course of murine malaria in three groups of mice with altered splenic function: congenitally asplenic mice, adult-splenectomized mice, and adult-splenectomized mice which were reconstituted with spleen-cell suspensions. intact mice infected with either plasmodium yoelii or p. chabaudi adami experienced infections which resolved spontaneously, with low mortality. congenitally asplenic and splenectomized-re ...	1980	7446805
immune phagocytosis of plasmodium yoelii-infected erythrocytes by macrophages and eosinophils.	unstimulated peritoneal cells from c57bl mice were allowed to phagocytose in vitro different mixtures of percoll-separated parasitized and non-parasitized erythrocytes (pe and npe) from the blood of mice infected with plasmodium yoelii in the presence of immune and normal serum. immune serum caused a significant enhancement of phagocytosis, and both the number of pe adhering to and/or ingested by 100 macrophages and the number of the latter cells engaged in phagocytosis was increased. the effect ...	1980	7460387
plasmodium yoelii: genetic analysis of crosses between two rodent malaria subspecies.		1981	7274370
hypergammaglobulinemia and erythrocyte autoantibody complicate enzyme immunoassay of antimalarial antibody.	enzyme immunoassay of specific antimalarial antibody in sera from plasmodium yoelii-infected mice was complicated by hypergammaglobulinemia and erythrocyte (rbc) autoantibody. malarious serum had higher immunoglobulin levels which resulted in a substantial nonspecific adsorption of antibody to antigen uncoated microliter wells even in the presence of a surfactant. since it was possible that some of the antibody binding to solid phase-bound malarial antigen was also due to nonspecific adsorption, ...	1981	7334130
plasmodium yoelii: antibody and the maintenance of immunity in balb/c mice.		1981	7238723
[studies on antimalarial drug. ii. the causal prophylactic activity of antimalarial in animal model. part i. plasmodium yoelii-anopheles stephensi system (author's transl)].		1981	7257809
host defenses in murine malaria: analysis of plasmodial infection-caused defects in macrophage microbicidal capacities.	macrophage-dependent killing of facultative intracellular bacteria was markedly impaired by overt erythrocytic plasmodium yoelii or plasmodium berghei infection of mice. p. yoelii infection was capable of ablating not only the macrophage microbicidal capacity of "normal" animals but also the bactericidal capacities of "activated" macrophages. the uptake by spleen and liver of an intravenous challenge of listeria monocytogenes was not altered by plasmodial infection, but within hours of injection ...	1981	7012000
immunization to produce a transmission-blocking immunity in plasmodium yoelii malaria infections.		1981	7268856
immunity to plasmodium chabaudi adami in the b-cell-deficient mouse.	immunity to malaria has a multicomponent basis which requires the participation of both t- and b-lymphocyte systems. previous studies have suggested that the t-lymphocyte system has an essential role in 're-infection immunity' to malaria, but that b cells and/or their products are necessary for the host to survive acute infection and to clear the blood of parasites during chronic malaria. thus, b-cell-deficient mice and chickens died of fulminant malaria when infected with plasmodium yoelii and ...	1981	6970898
[development of schizonts in cultured hepatocytes of adult rats after in vitro infection with plasmodium yoelii sporoazoites].	salivary glands of a. stephensi, containing p. yoelii' sporozoites, were disrupted and added to hepatocyte cultures originated from the liver of an adult rat perfused with a collagenase solution. 47 h after this in vitro inoculation, numerous well-developed and normal-looking schizonts were found in the hepatocyte monolayer.	1981	6797693
endotoxin-induced serum factor kills malarial parasites in vitro.	we investigated the possibility that malarial parasites may be killed by nonspecific soluble mediators, such as those in tumor necrosis serum, that are obtained from mice given macrophage-activating agents like corynebacterium parvum or mycobacterium bovis bcg, followed by endotoxin. such sera killed parasites in vitro after overnight incubation; killing was measured directly by using an in vivo infectivity assay. parasite infectivity was not decreased by incubation in sera from mice given c. pa ...	1981	7021427
monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii.	eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii. specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythr ...	1981	6166558
immunodepression of thymus-independent response to dextran in mouse malaria.	the thymus-independent antibody response to the alpha 1-6 epitope of dextran b512 was depressed strongly during acute non-lethal plasmodium yoelii yoelii malaria, but not during low-grade chronic plasmodium berghei infection. in the acute infection, which is self-limiting, the duration of severe immunodepression was short and was seen only in mice immunized at or around the time of peak parasitaemia. mice primed at this time responded normally to challenge 20 days later: thus the primary exposur ...	1981	6167386
plasmodium yoelii: comparison of indirect immunofluorescence and radioimmunoassay for detecting monoclonal antibodies to malaria.		1982	6177548
[system model of plasmodium yoelii--anopheles stephensi for screening tissue schizontocides].		1982	6217911
antimalarial activity of inhibitors of adp-ribosyl transferase against plasmodium yoelii infection in mice. 1. preliminary data.		1982	6128898
genetics of cross-resistance between antifolate drugs in plasmodium yoelii.		1982	6210768
the role of the kupffer cell in the infection of rodents by sporozoites of plasmodium: uptake of sporozoites by perfused liver and the establishment of infection in vivo.	the uptake of plasmodium yoelii nigeriensis sporozoites by isolated perfused rat liver was very rapid and efficient. 67% of the initial load was removed from the perfusion media in the first passage through the liver, and 95% after 15 min of perfusion. much of the uptake was explained by mechanical trapping in the liver. up to 75% of the sporozoite load was retained after 15 min both by heat killed liver and liver cooled to 4 degrees c, therefore at least 20% of the sporozoite uptake in perfused ...	1982	6122359
differential sensitivity in vivo of lethal and nonlethal malarial parasites to endotoxin-induced serum factor.	sera from mice infected with plasmodium yoelii or plasmodium berghei and given endotoxin contained nonspecific mediators which killed both species of parasite and tumor cells in vitro. the sera resembled tumor necrosis sera obtained from mice given macrophage-activating agents such as propionibacterium acnes (formerly designated corynebacterium acnes) or mycobacterium bovis bcg and then endotoxin. cytotoxicity developed parallel to parasite killing activity and indicated that macrophages were ac ...	1982	6752029
antimalarial activity of floxacrine (hoe 991) ii: studies on causal prophylactic and blood schizontocidal action of floxacrine and related dihydroacridinediones against plasmodium yoelii and p. berghei.		1982	6760821
interactions between the intestinal flagellates giardia muris and spironucleus muris and the blood parasites babesia microti, plasmodium yoelii and plasmodium berghei in mice.	in mice infected with the intestinal flagellates giardia muris or spironucleus muris, together with the blood parasites babesia microti or plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. this decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. the effect on s. muris is more marked than that on g. muris. neither blood p ...	1982	6214756
studies on the role of host serum in the retention of malarial sporozoites by isolated perfused rat liver.	the binding of host serum components to malarial sporozoites has been proposed as a mechanism for the specific phagocytic uptake of these parasites, and hence the specificity of host infection (schulman et al., 1981). we therefore observed the kinetics of uptake of sporozoites of plasmodium yoelii nigeriensis and p. gallinaceum by isolated perfused rat livers in the presence of homologous or heterologous sera. in the homologous system (p. y. nigeriensis sporozoites in rat serum) sporozoite uptak ...	1982	7080155
vaccination to prevent transmission of plasmodium yoelii malaria.	it was possible to block the transmission of infection of the rodent malaria parasite plasmodium yoelii nigeriensis to anopheles stephensi mosquitoes by immunizing mice with a vaccine containing formalin-fixed gametes. both intramuscular and intravenous routes were effective, immunity was achieved with a single dose and the immunity persisted for 6 months at least. transmission-blocking immunity was found to reside in a serum factor, probably antibody, and to be directed against extracellular ga ...	1982	7070834
killing of the malarial parasite plasmodium yoelii in vitro by cells of myeloid origin.	cytotoxic effects of mouse cells on plasmodium yoelii were sought directly by incubating parasitized red cells with cells of various kinds for 16 h and then determining the percentage parasite survival in vivo, in terms of infectivity for the mouse. cell populations rich in lymphocytes, e.g. lymph node and spleen, were less active than peritoneal cells and blood. parasite killing by peritoneal cells was associated with macrophages: treatment with anti-macrophage serum (ams) or depletion by adher ...	1982	7070836
[retarded schizogony of plasmodium yoelii yoelii in rodents treated with ethionine or subjected to a methionine deficiency: histological and ultrastructural studies].	histological and ultrastructural aspects of acute and chronic pre-erythrocytic schizonts of p. yoelii yoelii were studied with: a) acute schizonts in normal rodents; b) chronic schizonts induced in rodents receiving ethionine injections or on a low methionine diet; experimentally induced chronic schizonts frequently have the same histological aspect as those observed in wild thamnomys from africa. the ultrastructural evolution of the vacuole system described by seureau et al. in acute schizonts ...	1982	7081885
absence of effects of insecticides on susceptibility of anophelines to plasmodium yoelii nigeriensis.		1982	6810475
[in vitro infestation of adult thamnomys hepatocytes with plasmodium yoelii sporozoites; schizogony and release of infecting merozoites].	hepatocytes isolated from an african rodent, thamnomys gazellae, by perfusing the liver with a solution of collagenase were cultured in modified mem medium, and infected in vitro by sporozoites of the 17 x strain of p. y. yoelii. 48 hrs. later, schizonts measuring 30 to 40 microns on average were observed in all cultures. injection of culture supernatant, harvested on day 3, into mice, was followed by a parasitaemia demonstrating that viable merozoites had been released by the schizonts.	1982	6814716
a cage replacement experiment involving introduction of genes for refractoriness to plasmodium yoelii nigeriensis into a population of anopheles gambiae (diptera: culicidae).		1982	7086849
survival of mice injected with plasmodium vinckei or plasmodium yoelii xl by the footpad route.	nih-white mice were injected with varying doses of plasmodium vinckei or plasmodium yoelii lethal via the hind footpad (fp), intraperitoneal (ip), subcutaneous (sc) routes. survival was dependent on the dose of the inoculum and route of injection. injection via the ip and sc routes led to higher mortality than the fp route. the results showed that at a dose of 10 4 parasitized erythrocytes injected ip led to 100% mortality, whereas the same dose injected via the fp route gave protection.	1982	7125059
inhibition by cyclosporin a of rodent malaria in vivo and human malaria in vitro.	the development and course of normally lethal parasitemias in mice inoculated intraperitoneally with erythrocytic stages of plasmodium yoelii or plasmodium berghei were markedly affected by treatment with the antilymphoid drug cyclosporin a (cs-a). when the first of four daily subcutaneous 25-mg/kg doses of cs-a was given at the time of parasite inoculation, patent infections failed to develop. if begun up to 5 days earlier, this same treatment regimen prolonged the prepatent period, attenuated ...	1982	6752020
susceptibility of anopheles gambiae to plasmodium yoelii nigeriensis and plasmodium falciparum.		1982	6763502
murine malaria: blood clearance and organ sequestration of plasmodium yoelii-infected erythrocytes.	this study examined the mechanisms of clearance of plasmodium yoelii-infected erythrocytes (rbc) from the peripheral circulation of mice. parasitized rbc labeled with 51cr were cleared from the blood of normal c57bl/6 mice at a much more rapid rate than were nonparasitized rbc, and preincubation of parasitized rbc in antiplasmodial antibody failed to significantly enhance clearance. this apparent antibody-independent clearance mechanism was markedly abrogated by splenectomy, indicating a major r ...	1982	7141688
the rodent malaria parasite plasmodium yoelii lacks both types 1 and 2 t-independent antigens.		1982	6977572
t cell-mediated immunity in malaria. i. the ly phenotype of t cells mediating resistance to plasmodium yoelii.	cba mice that recover from plasmodium yoelii 17x infection are resistant to reinfection. t cells from these mice transfer immunity to nonimmune recipients. to analyze the nature and mode of action of these t cells, we transferred selected subsets into t cell-deprived recipients. treatment of the t cells with anti-ly-1 but not anti-ly-2 serum and c abrogated their ability to transfer immunity. a mixture of anti-ly-1 and anti-ly-2 serum-treated cells (i.e., a population devoid of ly-123 cells) tra ...	1982	6979570
[in vitro infection of adult thamnomys hepatocytes by sporozoites of plasmodium yoelii: development of schizonts and release of infective merozoites].		1982	7081893
elevated levels of phospholipase b in mice infected and challenged with plasmodium yoelii.	marked increases in phospholipase b activity were measured in spleen homogenates and sera of cd-1 mice given a primary infection of plasmodium yoelii. the rise in enzyme activity paralleled parasitemia and splenomegaly, all reaching maximum values 14 days after infection. maximum enzyme activity and splenomegaly were noted 5 days after challenge in mice given a secondary infection indicating an anamnesticlike response following a subsequent contact with the infecting parasite. these observations ...	1982	7131182
[immediate inhibition of the infectivity of gametocytes of plasmodium yoelii nigeriensis by serum from rodents infected for 5 days].		1982	7181381
a comparison of saponin with other adjuvants for the potentiation of protective immunity by a killed plasmodium yoelii vaccine in the mouse.	the protective immunity conferred by subcutaneous injection of outbred cd-1 mice with a killed plasmodium yoelii (ym strain) vaccine was strongly potentiated by saponin. by adjusting the dose of antigen, the number of immunizations and the number of living parasites in the challenge infection, conditions were defined where antigen alone was non-protective but 100% protection was obtained by the addition of saponin. inbred balb/c, cba/ca and c57 b1 mice were much less responsive than the cd-1 mic ...	1982	7145465
murine malaria: cellular interactions in the immune response.	the cellular and humoral interactions that contribute to protective immunity in plasmodium yoelii malaria were studied by adoptive transfer of selective cell populations or hyperimmune serum into sublethally irradiated syngeneic c57bl/6 mice. for some experiments pools of mononuclear spleen cells were depleted of t or b lymphocytes and cells that take up silica were inactivated by standard procedures. unfractionated immune spleen cells, but not nonimmune spleen cells, protected recipients from l ...	1983	6606366
experimentally derived, stable mefloquine resistance in plasmodium yoelii nigeriensis.		1983	6602406
specific lysis of plasmodium yoelii infected mouse erythrocytes with antibody and complement.	an assay for complement-dependent antibody-mediated cytolysis of plasmodium yoelii infected mouse erythrocytes was designed. by means of a rat hyperimmune serum to p. yoelii the presence of parasite associated antigens was demonstrated on erythrocytes from p. yoelii infected mice. tests with such erythrocytes fractionated on percoll gradients showed that the target antigens for the cytotoxic antibodies were confined to the surface of only infected erythrocytes containing late stages of the paras ...	1983	6861370
killing of blood-stage murine malaria parasites by hydrogen peroxide.	both nonlethal plasmodium yoelii and lethal plasmodium berghei were killed in vitro by hydrogen peroxide at concentrations as low as 10(-5) m. higher concentrations were required in the presence of added normal erythrocytes. injection of hydrogen peroxide in vivo significantly reduced p. yoelii parasitemia but had less effect on p. berghei.	1983	6822428
observations on the morphology and electrophoretic variation of enzymes of the rodent malaria parasites of cameroon, plasmodium yoelii, p. chabaudi and p. vinckei.	six samples of rodent blood infected with malaria parasites were isolated from cameroon. of these, 2 contained mixed infections of plasmodium vinckei and p. yoelii, 3 contained p. vinckei alone and 1 p. chabaudi alone. each isolate was cloned and the resulting lines examined for morphology of blood and mosquito forms, and for electrophoretic variation in enzymes. the p. chabaudi and p. yoelii lines were morphologically and enzymically identical to isolates of the central african republic. simila ...	1983	6856331
histopathology and histochemistry of r.e.s. in infections with plasmodium yoelii nigeriensis.		1983	6631099
characteristics of the protective response of balb/c mice immunized with a purified plasmodium yoelii schizont antigen.	the response of balb/c mice to immunization with a 230,000 mol. wt protective antigen purified from the blood stages of plasmodium yoelii was analysed. the protective response to immunization was adjuvant-dependent, and saponin was found to be the most effective adjuvant tested. the intraperitoneal route was found to be superior to the subcutaneous route for protective immunization. maximal protection was achieved using two immunizations with greater than 12.5 micrograms of antigen plus saponin, ...	1983	6652973
plasmodium yoelii: blood oxygen and brain function in the infected mouse.	the carriage of oxygen by the blood and the in vivo response of the brain were investigated in mice infected with a lethal strain of plasmodium yoelii. all mice with parasitaemia exceeding 70% were severely anaemic (hb 3.5 +/- 1.8 g/dl; mean +/- 1 sd), acidotic (blood ph 7.04 +/- 0.06) and hypoglycaemic (blood glucose 0.6 +/- 0.76 mumol/ml). the oxyhaemoglobin dissociation curve (odc) of blood from heavily infected mice was shifted right as compared to controls, but the increase in p50 was less ...	1983	6641896
enhanced expression of h-2k and h-2d antigens on reticulocytes infected with plasmodium yoelii.	the 17xnl strain of plasmodium yoelii induces a highly effective and permanent t-cell dependent immunity in mice of the cba strain; the lethal variant p. yoelii 17xl and p. berghei (anka) fail to activate an effective immune response in the same host. these differences in immunogenicity are unexplained. we recently observed that in cba/caj mice the intracellular blood stages of p. yoelii 17xnl were almost exclusively within reticulocytes whereas lethal p. yoelii 17xl and p. berghei (anka), at co ...	1983	6339952
the role of cell-mediated immune responses in resistance to malaria, with special reference to oxidant stress.	asexual blood forms of malaria parasites are microaerophilic and sensitive to oxidant stress. plasmodium falciparum and some other species of malaria parasites undergo schizogony attached to endothelial cells of postcapillary venules, where oxygen tensions are low. acquired immune responses to all forms of malaria parasites so far investigated are thymus dependent. animals deprived of t lymphocytes do not recover from the infections and cannot be immunized against malaria parasites. in contrast, ...	1983	6100538
adp-ribosyltransferase in plasmodium (malaria parasites).	the nuclei of plasmodium yoelii nigeriensis contain an enzyme, adp-ribosyltransferase, that will incorporate the adp-ribose moiety of nad+ into acid-insoluble product. the time, ph and temperature optima of this incorporation are 30 min, 8.5 and 25 degrees c respectively. maximum stimulation of the enzyme activity is obtained with 1.0 mm-dithiothreitol or 2.0 mm-2-mercaptoethanol. ca2+ and mg2+ ions at optimum concentrations of 5 mm and 10 mm respectively stimulated the activity of the enzyme by ...	1983	6307262
endoprotease in plasmodium yoelii nigeriensis.	1. p. yoelli nigeriensis has an acid endoprotease (cathepsin d) and an endoarylamidase. 2. the acid endoprotease is specific towards haemogloblin. it is found in 2 molecular forms, of molecular weight 100,000 and 50,000. it is inhibited by hematin and pepsatin. 3. in mouse normal red blood cells we find an acid protease having physico-chemical properties similar to those of the enzyme present in p. yoelii nigeriensis extracts, except as regards the phi. 4. in parasite extracts there exists an en ...	1983	6340950