Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| protective plasmodium knowlesi mr 74,000 antigen in membranes of schizont-infected rhesus erythrocytes. | the immunogenic plasmodium knowlesi (h strain) mr 74,000 protein in membranes of schizont-infected rhesus erythrocytes was purified on a large scale, free of other polypeptides as monitored by dodecyl sulfate polyacrylamide gel electrophoresis and isoelectric focusing. in a limited vaccination trial, four rhesus monkeys were immunized four consecutive times with the mr 74,000 protein and freund's complete and incomplete adjuvants. two monkeys were injected with adjuvant only. upon challenge with ... | 1983 | 6190975 |
| antigenic variation of plasmodium knowlesi malaria: identification of the variant antigen on infected erythrocytes. | erythrocytes infected with mature asexual stages of plasmodium knowlesi express a new surface antigen such that rhesus monkey antisera specifically agglutinate these cells. cloned parasites can express different antigenic variants of this antigen. the variant antigen has been identified by comparison of the surface membrane antigens of a clone and of an antigenic variant of that clone of different agglutination phenotype. after lactoperoxidase labeling, 125i-labeled proteins of mrs 210,000 and 1 ... | 1983 | 6191331 |
| identification and chemical synthesis of a tandemly repeated immunogenic region of plasmodium knowlesi circumsporozoite protein. | complementary dna clones that code for the immunogenic region of the plasmodium knowlesi circumsporozoite protein were shown to contain a tandemly repeating 36-base pair unit. a synthetic dodecapeptide corresponding to the predicted reading frame of the repeating nucleotide unit behaved, in an immunoradiometric assay, identically with the native p. knowlesi circumsporozoite protein. the repeating 36-base pair unit occurred 12 times within the gene and accounts for at least one-third of the amino ... | 1983 | 6193427 |
| evidence for immunological cross-reaction between sporozoites and blood stages of a human malaria parasite. | malaria parasites (plasmodium spp.) show a complex pattern of development in the mammalian host and many studies support the view that the surface of the sporozoite, injected by the mosquito, has no antigens in common with the erythrocytic stage of development. for example, immunization with the erythrocytic parasites generates antisera with negligible titre by indirect immunofluorescence to the sporozoite surface. although monoclonal antibodies prepared against erythrocytic stages were reported ... | 1984 | 6199678 |
| immunological detection of plasmodium knowlesi antigens after electrophoretic transfer from sds-polyacrylamide gels to diazophenylthioether paper. | freeze-thawed extracts of mature schizonts of plasmodium knowlesi (strain w1) were electrophoresed in sodium dodecylsulphate (sds) polyacrylamide gels, then transferred electrophoretically to diazophenylthioether paper. the transferred antigen was probed using a purified polyvalent, polyclonal immune serum pool isolated from rhesus monkeys (macaca mulatta). this method for identifying parasite antigens was compared with immunoabsorption, using parasites which had been metabolically labelled in v ... | 1984 | 6199719 |
| plasmodium knowlesi sporozoite antigen: expression by infectious recombinant vaccinia virus. | the gene coding for the circumsporozoite antigen of the malaria parasite plasmodium knowlesi was inserted into the vaccinia virus genome under the control of a defined vaccinia virus promoter. cells infected with the recombinant virus synthesized polypeptides of 53,000 to 56,000 daltons that reacted with monoclonal antibody against the repeating epitope of the malaria protein. furthermore, rabbits vaccinated with the recombinant virus produced antibodies that bound specifically to sporozoites. t ... | 1984 | 6200932 |
| structure of the gene encoding the immunodominant surface antigen on the sporozoite of the human malaria parasite plasmodium falciparum. | the gene for the circumsporozoite (cs) protein of plasmodium falciparum has been cloned and its nucleotide sequence determined. the gene encodes a protein of 412 amino acids as deduced from the nucleotide sequence. the protein contains 41 tandem repeats of a tetrapeptide, 37 of which are asn-ala-asn-pro and four of which are asn-val-asp-pro. monoclonal antibodies against the cs protein of plasmodium falciparum were inhibited from binding to the protein by synthetic peptides of the repeat sequenc ... | 1984 | 6204383 |
| structure of an immunodominant epitope of the circumsporozoite surface protein of plasmodium knowlesi. | previous studies have shown that the immunodominant region of the circumsporozoite surface (cs) protein of plasmodium knowlesi is contained within a tandemly repeated dodecapeptide: gln-ala-gln-gly-asp-gly-ala-asn-ala-gly-gln-pro. we show here that the cs protein epitopes reacting with six monoclonal antibodies raised against the intact parasite are represented in a synthetic tandem repeat of this dodecapeptide. the specificity of four of these antibodies was studied further by preparing synthet ... | 1984 | 6210107 |
| plasmodium knowlesi: glycolytic intermediate levels of enzyme activities of infected rhesus monkey erythrocytes. | 1982 | 6211368 | |
| inhibition of malaria parasite invasion into erythrocytes pretreated with membrane-active drugs. | normal rhesus monkey erythrocytes were incubated with various membrane-active drugs (for 1 h at 37 degrees c) and after thorough washing, were exposed to infection with plasmodium knowlesi in an invitro cultivation system. the ability of merozoites to infect with drug-pretreated erythrocytes was assessed both by counting the number of infected cells and by measuring the incorporation of [3h]isoleucine into parasite protein. marked inhibition of invasion was observed with vinblastine and colchici ... | 1980 | 6255328 |
| structure of the plasmodium knowlesi gene coding for the circumsporozoite protein. | the gene that codes for the surface antigen of plasmodium knowlesi sporozoites (cs protein) is unsplit and present in the genome in only one copy. the cs protein, as deduced from dna sequence analysis of the structural gene, has an unusual structure with the central 40% of the polypeptide chain present as 12 tandemly repeated amino acid peptide units flanked by regions of highly charged amino acids. the protein has an amino-terminal hydrophobic amino acid signal sequence and a hydrophobic carbox ... | 1983 | 6313209 |
| hematologic and immunologic responses in common marmosets (callithrix jacchus) infected with plasmodium knowlesi and epstein-barr virus. | the hematologic and immunologic responses to infection with either the epstein-barr virus alone or infection with epstein-barr virus and plasmodium knowlesi were studied using common marmosets (callithrix jacchus). the assays performed included complete blood cell counts, determinations of natural killer cell activity, and determinations of antibody titers to epstein-barr virus early antigen, virus capsid antigen and the nuclear antigen. while no animal showed signs of lymphoproliferative diseas ... | 1984 | 6328114 |
| effect of chloroquine treatment on complement levels in plasmodium knowlesi infected rhesus monkeys. | 1984 | 6336062 | |
| changes in concentration of lymphocytes subpopulations in rhesus monkey during plasmodium knowlesi infection and in drug-cured immune monkeys. | 1984 | 6336063 | |
| resistance of melanesian elliptocytes (ovalocytes) to invasion by plasmodium knowlesi and plasmodium falciparum malaria parasites in vitro. | erythrocytes from humans with melanesian elliptocytosis are resistant to invasion by plasmodium falciparum in vitro and epidemiological evidence suggests they may be resistant to p. vivax and p. malariae. we have examined the ability of p. knowlesi merozoites to invade melanesian elliptocytes in vitro as a definitive means of examining these cells for resistance to invasion by malarial species with different receptor requirements. the melanesian elliptocytes were highly resistant to invasion by ... | 1983 | 6338046 |
| cloning and expression in e. coli of the malarial sporozoite surface antigen gene from plasmodium knowlesi. | the malarial sporozoite, the infective stage found in the salivary gland of the insect vector, bears highly immunogenic surface antigen(s). repeated exposure to irradiated sporozoites induces protection against malaria in several host species, including man. further, monoclonal antibodies that confer passive immunity react with the immunogenic surface determinants of different sporozoite species. one approach to prevent malaria, therefore, would be to produce a vaccine that induces high titres o ... | 1983 | 6339949 |
| influence of the spleen on the expression of surface antigens on parasitized erythrocytes. | two malaria parasites, plasmodium knowlesi and p. falciparum, when passaged in splenectomized hosts alter or fail to express parasite-dependent antigens on the surface membrane of erythrocytes infected with mature parasites. experiments with cloned populations of p.knowlesi show this change to be phenotypic and to be modulated by the spleen of the host. in addition, the induction of antigen variation in p. knowlesi malaria apparently requires two factors: specific antibody and the spleen. along ... | 1983 | 6340998 |
| parasite polypeptides lost during schizogony and erythrocyte invasion by the malaria parasites, plasmodium chabaudi and plasmodium knowlesi. | 1983 | 6341836 | |
| the malaria merozoite surface: a 140,000 m.w. protein antigenically unrelated to other surface components on plasmodium knowlesi merozoites. | we previously identified three proteins on the surface of merozoites (140,000, 105,000 and 75,000 m.w.). to determine if 140,000 m.w. protein was related to other surface proteins, we immunized mice with liposomes containing merozoite proteins from the 140,000 m.w. region of the polyacrylamide gel. the immune sera reacted with the surface of viable merozoites and acetone-fixed schizonts by immunofluorescence. the sera immunoprecipitated only the 140,000 m.w. protein from surface-labeled merozoit ... | 1983 | 6343487 |
| enzyme-linked immunosorbent assay test with plasmodium knowlesi antigen in diagnosis of malaria. | 1983 | 6347882 | |
| comparative evaluation of plasmodium knowlesi and p. cynomolgi antigens in the indirect fluorescent antibody test for human malaria. | 1983 | 6352471 | |
| evidence of trapped red cells in the brain of rhesus monkey infected with plasmodium knowlesi. | 59fe-labelled normal red cells and 51cr-labelled p. knowlesi infected red cells were used as tracers for a study on the trapped red cells in the brain of rhesus monkeys infected with p. knowlesi. after instantaneous injection into a common carotid artery, blood was sampled from both of the internal jugular veins at various intervals. results in 6 experiments on 3 infected monkeys showed that about 17% of infected red cells given was trapped in the capillaries of the brain of the infected monkeys ... | 1983 | 6369558 |
| identification of parasite proteins in a membrane preparation enriched for the surface membrane of erythrocytes infected with plasmodium knowlesi. | a subcellular fraction enriched in erythrocyte membranes has been isolated from rhesus monkey erythrocytes infected with plasmodium knowlesi. infected cells were lysed by centrifugation through a zone of hypotonic buffer and membranes isolated by equilibrium density gradient centrifugation in the same tube. the purified membrane fraction was shown to include the erythrocyte surface membrane by several methods: electron microscopy, identification of coomassie blue stained erythrocyte membrane pro ... | 1984 | 6379454 |
| a reevaluation of the status of cholesterol in erythrocytes infected by plasmodium knowlesi and p. falciparum. | the cholesterol synthesis of rhesus monkey erythrocytes parasitized by plasmodium knowlesi and human erythrocytes infected by p. falciparum, as measured by incorporation of [1-14c]acetate and 3h2o, was almost undetectable, concordant with very low levels of measurable 3-hydroxy-3-methyl glutaryl-coa reductase activity. in addition, both types of infected cells exchanged cholesterol with the plasma at the same rate as uninfected cells. the data do not exclude the possibility of cholesterol transf ... | 1984 | 6392884 |
| studies on the glomerular filtration rate and extracellular fluid volume in rhesus monkeys infected with plasmodium knowlesi. | the glomerular filtration rate (gfr) and the extracellular fluid volume (ecv) were determined in 5 rhesus monkeys infected with p. knowlesi in comparison with 6 control monkeys by using 51cr-edta. as the disappearance curve of the radioactivity showed a close fit to a double exponential equation, the data was therefore analysed by an open 2-compartment system. results in the present study showed that the gfr was significantly reduced in the infected group. both v1 and v2 were also slightly but n ... | 1984 | 6441266 |
| neutralization of the infectivity of sporozoites of plasmodium knowlesi by antibodies to a synthetic peptide. | antibodies against a synthetic peptide representing the repetitive epitope of the circumsporozoite protein (cs) of plasmodium knowlesi have properties similar to those of antibodies against the native protein. either antibody reacts with the synthetic peptide, cross-links the cs protein on the membrane of the parasite giving the csp reaction, and neutralizes the infectivity of sporozoites. the synthetic peptide and sporozoite extracts were equally effective when used in an immunoradiometric assa ... | 1984 | 6470623 |
| the fab fragments of monoclonal igg to a merozoite surface antigen inhibit plasmodium knowlesi invasion of erythrocytes. | two rat monoclonal antibodies (both igg2a isotype and having closely related specificities) and a pool of rhesus immune igg, all of which inhibit plasmodium knowlesi merozoite invasion of rhesus erythrocytes, have been studied before and after proteolytic digestion. the f(ab')2 and fab fragments of both rat monoclonal antibodies show considerably enhanced inhibition of merozoite invasion as compared with the intact igg. inhibition by monovalent fragments indicates that these antibodies are not d ... | 1984 | 6513992 |
| influence of progesterone and estrogen administration on the recrudescence patterns of plasmodium knowlesi infection in female rhesus monkeys (macaca mulatta) following initial subcurative chloroquine therapy. | 1984 | 6536543 | |
| an evaluation of plasmodium cynomolgi bastianellii and plasmodium knowlesi antigens in the seroepidemiology of human malaria using indirect haemagglutination test. | 1984 | 6536544 | |
| the blood schizontocidal action of erythromycin against plasmodium knowlesi infections in macaca mulatta. | chloroquine-induced pigment clumping (cipc) in vitro in plasmodium knowlesi is inhibited by 7.3 micrograms ml-1 erythromycin. p. knowlesi infections in rhesus monkeys were controlled by doses of erythromycin which gave similar serum levels of the antibiotic. the antimalarial effect was complete but temporary, and recrudescences were noted. | 1983 | 6625724 |
| a monoclonal antibody to rhesus erythrocyte band 3 inhibits invasion by malaria (plasmodium knowlesi) merozoites. | receptors on erythrocytes and malaria parasites mediate specific attachment and junction formation between these cells that lead to invasion of the erythrocytes. we identified monoclonal antibody a9 and its subclone a9d3 that bound to rhesus erythrocytes and blocked invasion of the erythrocytes by plasmodium knowlesi merozoites. the monoclonal antibodies did not block attachment, the initial step in invasion, although swelling and crenation of the erythrocyte, which normally occur after attachme ... | 1983 | 6630511 |
| a note on micro in vitro technique for screening antimalarials using plasmodium knowlesi. | 1983 | 6630985 | |
| trapped red cell volume in rhesus monkeys infected with plasmodium knowlesi. | 1983 | 6635771 | |
| monoclonal antibodies to a 140,000-m.w. protein on plasmodium knowlesi merozoites inhibit their invasion of rhesus erythrocytes. | merozoites are the invasive stage of the malaria parasite, which are released from infected erythrocytes to invade other erythrocytes. antibody to surface antigens on merozoites may prevent invasion by agglutinating merozoites as they are released from infected erythrocytes or by blocking receptors before contact of merozoites with the host erythrocyte. monoclonal antibodies were produced to a 140,000-m.w. protein on the merozoite surface. the protein was synthesized by the mature intraerythrocy ... | 1984 | 6690607 |
| plasmodium knowlesi: persistence of transmission blocking immunity in monkeys immunized with gamete antigens. | eight rhesus monkeys immunized with a partially purified preparation of plasmodium knowlesi gametes were monitored for over 6 years to determine the extent of transmission blocking immunity. monkeys were challenged regularly, and anti-gamete antibodies were assayed by in vivo and in vitro mosquito feedings. transmission blocking immunity persisted at high levels in most of the monkeys. in those animals in which protection waned between challenges, a challenge infection provided a sufficient boos ... | 1984 | 6706402 |
| solubilization and immunoprecipitation of 125i-labelled antigens from plasmodium knowlesi schizont-infected erythrocytes using non-ionic, anionic and zwitterionic detergents. | plasmodium knowlesi malaria-infected erythrocytes were radio-iodinated and several non-ionic, anionic and zwitterionic detergents were compared in their capacity to extract the labelled membrane proteins. the use of these detergents for antigen identification was tested by immunoprecipitation, after addition of triton x-100 to some detergent extracts, using hyperimmune monkey antiserum and protein a-sepharose. 125i-labelled antigens were specifically immunoprecipitated with all detergents tested ... | 1984 | 6709393 |
| immuno-electron microscopic observations on plasmodium knowlesi sporozoites: localization of protective antigen and its precursors. | cryoultramicrotomy, an antisporozoite monoclonal antibody (2g3) and protein a-gold particles were used to determine the distribution of the protective surface antigen (pk 42) of sporozoites of plasmodium knowlesi and its precursors (pk 52 and pk 50). gold particles bound uniformly to both the outer plasma and the inner pellicular membranes, indicating a uniform distribution of antigen on these membranes. intracellular gold particles were frequently found to be associated with micronemes, but les ... | 1984 | 6711740 |
| protein antigens of plasmodium knowlesi clones of different variant antigen phenotype. | mature asexual stages of the malaria parasite plasmodium knowlesi synthesize proteins of mr 180 000-225 000 that are expressed on the outer membrane of infected erythrocytes and which vary antigenically such that different parasite clones are specifically agglutinated with homologous antibody. other non-agglutinable clones have been prepared which fail to express variant antigen on infected cells. two agglutinable clones of different variant antigen phenotypes and a non-agglutinable cone were ex ... | 1984 | 6718054 |
| 2-mercapto-ethanol enhancement of agglutination reaction--a possible in vitro serological correlate for assessment of functional immunity in simian malaria. | conventional indirect haemagglutination test was performed in rhesus monkey sera (collected from plasmodium knowlesi infected animals) with and without prior treatment of sera with 2-mercapto-ethanol (2-me). surprisingly, many sera samples showed significant enhancement of final titre with 2-me. the 2-me enhancement effect was more pronounced in the sera of hyperimmune monkeys on further injection of antigen or parasites. it was also noticeable in the sera during primary drug-suppressed p. knowl ... | 1984 | 6724640 |
| the detergent solubility properties of a malarial (plasmodium knowlesi) variant antigen expressed on the surface of infected erythrocytes. | four detergents have been compared for identification of the plasmodium knowlesi variant antigen on infected erythrocytes by immunoprecipitation analysis. erythrocytes infected with late trophozoite and schizont forms of cloned asexual parasites were labeled by lactoperoxidase-catalyzed radioiodination and extracted either with the anionic detergents sodium dodecyl sulfate (sds) or cholate, the neutral detergent triton x-100, or the zwitterion 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sul ... | 1984 | 6736140 |
| biosynthesis of a putative protective plasmodium knowlesi merozoite antigen. | a putative protective plasmodium knowlesi antigen, recognized by two monoclonal antibodies which prevent invasion of erythrocytes by merozoites in vitro, is synthesised only by schizonts with 7 or more nuclei, during the last 1.5-2 h of the 24 h erythrocytic cycle of parasite development. the 66 000 mw antigen, which constitutes a minor parasite protein, is processed at the time of schizont rupture and merozoite release, to give rise to two smaller molecules of 44 000 and 42 000 mw. the 44 000 a ... | 1984 | 6749179 |
| processing of a major parasite surface glycoprotein during the ultimate stages of differentiation in plasmodium knowlesi. | a monoclonal antibody (13c11) was used to investigate the processing of a plasmodium knowlesi plasma membrane protein during the late stages of schizogony. 13c11 bound to the surface of merozoites, blocked invasion of erythrocytes and immunoprecipitated a 230 kda glycoprotein from metabolically labelled schizonts. this protein was a major parasite surface component inserted into the membrane of immature schizonts as shown through the study of saponin-freed schizonts which bound 13c11 to their su ... | 1984 | 6749183 |
| rat monoclonal antibodies which inhibit the in vitro multiplication of plasmodium knowlesi. | 1982 | 6751636 | |
| endopeptidases from plasmodium knowlesi. | extracts of rhesus monkey erythrocytes infected with plasmodium knowlesi were fractionated by polyacrylamide gel electrophoresis (page) and several zones of endopeptidase activity were demonstrated by an imprint-digest method. the enzymes were active only under acid conditions; activity was detected at ph 3.2 but not between ph 6.4 and 8.9 using haemoglobin, albumin or erythrocyte lysate as the substrate. optimized page conditions separated highly active parasite enzymes with rf values of 73, 63 ... | 1980 | 6768047 |
| plasmodium berghei and plasmodium knowlesi: serum binding to sporozoites. | 1980 | 6768578 | |
| factors affecting the ability of isolated plasmodium knowlesi merozoites to attach to and invade erythrocytes. | plasmodium knowlesi merozoites were prepared by the polycarbonate sieving method of dennis, mitchell, butcher & cohen (1975). merozoite function was assayed by their attachment to and invasion of rhesus erythrocytes at 37 degrees c. the early merozoites from the culture chamber were the most invasive, although maximum numbers of merozoites appeared later. merozoites were most stable when incubated at room temperature (23 degrees c). at 37 and 0 degrees c invasiveness rapidly declined to zero. at ... | 1980 | 6771738 |
| nuclear envelope - plasma membrane - compaction domain in malaria parasites. | a novel compaction domain between the nuclear envelope and the plasma membrane is observed in intraerythrocytic plasmodium knowlesi and plasmodium chabaudi. the plasma membrane and the two nuclear membranes stick very closely together thus forming a heptalamina domain. this has an outer diameter of 14.3 +/- 1.1 nm and can be as long as 2/um. fracture faces in this region appear to be devoid of the typical membrane-intercalating-particles. this compaction domain occurs only in ring-stages and ear ... | 1980 | 6772307 |
| alterations in the distribution and proliferative responses of rhesus monkey peripheral blood and spleen cells during malaria (plasmodium knowlesi) infection. | rhesus monkeys are used frequently as animal models in malaria research, but few studies have evaluated lymphocyte functions in these animals after experimental infections with the primate malarial parasite plasmodium knowlesi. in this study, the distribution and mitogen responses of mononuclear cells in the peripheral blood and spleens of 16 p. knowlesi-infected rhesus monkeys were followed. all animals included in the study developed acute infections and were bled out with parasitemias of more ... | 1980 | 6772559 |
| sporozoites of mammalian malaria: attachment to, interiorization and fate within macrophages. | sporozoites of plasmodium berghei and plasmodium knowlesi, incubated in normal serum readily interact with peritoneal macrophages of mice or rhesus monkeys, respectively. interiorization of the sporozoite requires that both serum and macrophages be obtained from an animal susceptible to infection by the malaria parasite. serum requirements for sporozoite attachment to the macrophage are less specific. phagocytosis is not essential for the parasites to become intracellular. our findings indicate ... | 1980 | 6772771 |
| malarial antigens on infected erythrocytes. | absorption experiments with washed membranes derived from erythrocytes infected with schizonts of plasmodium knowlesi (pe) showed that the antigen responsible for agglutination of pe in sica tests is firmly bound to membranes. further experiments demonstrated that the number of antibody binding sites at the surface of parasitized erythrocytes can be measured using iodinated globulins. the conditions under which this could be achieved have been defined and a preliminary estimate of the number of ... | 1980 | 6777912 |
| double diffusion analysis of antigens released from plasmodium knowlesi in vitro. | two parasite-derived antigens (designated band 1 and band 2) were identified upon double-diffusion analysis of culture medium from reinvading culture of p. knowlesi. band 1 antigen showed characteristics with the r-antigens of p. falciparum while the other was similar to the p. falciparum l-antigens. both antigens appeared to be largely particulate in character and did not display any obvious variant-specificity. analysis of plasma from rhesus monkeys infected with the same antigenic variant sho ... | 1981 | 6784369 |
| blood lymphocytes and serum protein in plasmodium knowlesi infection in a protein deficient host. | 1982 | 6816734 | |
| plasmodium knowlesi: studies on invasion of rhesus erythrocytes by merozoites in the presence of protease inhibitors. | the effect of protease inhibitors on invasion of rhesus erythrocytes by plasmodium knowlesi merozoites was evaluated. chymostatin, n-alpha-p-tosyl-l-lysine chloromethyl ketone (tlck), and l-1-tosylamide-2-phenylethylchloromethyl ketone (tpck) inhibited invasion. leupeptin, antipain, pepstatin, and phenylmethylsulfonyl fluoride (pmsf) had no effect. tlck and tpck inhibited attachment of merozoites to host erythrocytes. chymostatin had no adverse effect on attachment, and in its presence junction ... | 1983 | 6852169 |
| stage-specific protein synthesis by asexual blood stage parasites of plasmodium knowlesi. | p. knowlesi parasites with a maximum age distribution of 3 h were metabolically labelled with [35s]methionine during 9 sequential non-overlapping intervals, from young rings to mature segmented schizonts. the proteins synthesised at the different stages were compared using sodium dodecyl sulphate-polyacrylamide gel electrophoresis; more than 40 polypeptides (mr 20 000 to over 200 000) were identified in the different parasite preparations. the major polypeptides synthesised by rings and trophozo ... | 1983 | 6877279 |
| monoclonal antibodies identify the protective antigens of sporozoites of plasmodium knowlesi. | nine monoclonal antibodies against surface antigens of sporozoites of the simian malaria parasite plasmodium knowlesi were produced by fusion of plasmacytoma cells with spleen cells of a mouse immunized with the parasites. immunoprecipitation of extracts of [35s]methionine-labeled sporozoites with seven of the monoclonals identified the same three polypeptides with apparent molecular weights of 52,000 (pk52), 50,000 (pk50) and 42,000 (pk42). these antigens also were recognized by serum of a rhes ... | 1982 | 6957883 |
| antimalarial activity of mefloquine and chloroquine against blood induced plasmodium knowlesi infection in rhesus monkeys. | 1981 | 6974694 | |
| circulating immune complexes in plasmodium knowlesi infected kra, and merozoite vaccinated rhesus monkeys. | the presence of circulating soluble immune complexes that bind the c1q component of complement has been determined in the sera of two monkey species showing different degrees of clinical immunity to plasmodium knowlesi infection. material binding c1q was found in the serum of both primarily infected kra monkeys and post-vaccinated immune rhesus monkeys following the onset of parasitaemia. the complexes then disappeared from the circulation of kra monkeys despite continuing low-grade parasitaemia ... | 1982 | 6980742 |
| involvement of malarial proteases in the interaction between the parasite and host erythrocyte in plasmodium knowlesi infections. | the effect of protease inhibitors obtained from the culture filtrates of actinomycetes (pepstatin, chymostatin, leupeptin, phosphoramidon and elastatinal) on the in vitro invasion of erythrocytes from rhesus and assamese monkeys by plasmodium knowlesi merozoites was studied. the presence of these inhibitors had no effect on release of merozoites from schizonts but inhibited entry of the parasite into the red cell. thus, at 50 micrograms/ml, chymostatin and leupeptin completely blocked the invasi ... | 1981 | 7028937 |
| congenital transfer of antibodies against malarial sporozoites detected in gambian infants. | a survey of the antibody response to sporozoites of plasmodium falciparum was carried out on plasma samples obtained from 20 mothers and their newborn infants living in the gambia, west africa. serological assays detected antisporozoite antibodies in 90% (18/20) of the mothers, and similar titers were detected in 17/18 of their infants. the antisporozoite antibodies were gradually lost from the circulation of the babies until by approximately 6 months of age positive reactions against p. falcipa ... | 1981 | 7034558 |
| immunogenic antigens common to plasmodium knowlesi and plasmodium falciparum are expressed on the surface of infected erythrocytes. | sera of gambian individuals and rhesus monkeys immune against infections with plasmodium falciparum and plasmodium knowlesi, respectively, were reacted with triton x-100-solubilized membranes of infected erythrocytes. indirect immune precipitation with staphylococcus aureus, cowan strain a, followed by dodecylsulfate-polyacrylamide gel electrophoresis, were used to identify interspecies plasmodial antigens that were immunogenic in vivo. both types of sera specifically precipitated plasmodium-spe ... | 1982 | 7042947 |
| failure to detect hypnozoites in hepatic tissue containing exoerythrocytic schizonts of plasmodium knowlesi. | sections of paraffin-embedded rhesus liver containing numerous nearly mature exoerythrocytic schizonts of the non-relapsing malaria parasite, plasmodium knowlesi, were examined for the presence of hypnozoites by indirect immunofluorescence, employing both homologous and strongly cross-reacting heterologous sera. no hypnozoites or evident hypnozoite equivalents were detected in tissue which, by analogy with results obtained for the relapsing species, p. cynomolgi bastianellii, should have contain ... | 1982 | 7048949 |
| purine and pyrimidine nucleotide profiles during synchronous malaria infection (plasmodium knowlesi) in the rhesus monkey. | 1982 | 7068328 | |
| serological studies in plasmodium knowlesi infected convalescent rhesus monkeys. | 1982 | 7085017 | |
| intraerythrocytic development of plasmodium knowlesi: structure, temperature- and ca2+-response of the host and parasite membranes. | thin-sectioning and freeze-etching electron microscopy were applied to explore the structure and the temperature- and ca2+-response of the different host and parasite membranes during intraerythrocytic development of plasmodium knowlesi in macaca mulatta. the plasma membrane of uninfected erythrocytes is temperature- and ca2+-responsive: chilling to 4 degrees c and exposure to 5 mm ca2+ induces a slight decrease in imp-frequency and the emergence of small imp-devoid patches on p-faces. on parasi ... | 1982 | 7086712 |
| phospholipid biosynthesis by plasmodium knowlesi-infected erythrocytes: the incorporation of phospohlipid precursors and the identification of previously undetected metabolic pathways. | metabolic pathways leading to phospholipid biosynthesis in plasmodium-infected simian erythrocytes were tested and quantified by incubating leucocyte-free erythrocytes in the presence of labelled precursors. plasma fatty acids and lysophospholipids both served as sources of the fatty acids required for cellular phospholipid biosynthesis. however, the entry of free fatty acids and lysophospholipids appeared to be controlled by a competitive mechanism. a powerful deacylase-acylase system was detec ... | 1982 | 7097440 |
| radioiodination of new protein antigens on the surface of plasmodium knowlesi schizont-infected erythrocytes. | 1982 | 7162531 | |
| tritiation of protein antigens of plasmodium knowlesi schizont-infected erythrocytes using pyridoxal phosphate-sodium boro [3h]hydride. | 1982 | 7162532 | |
| bonnet monkey (macaca radiata) as a suitable host for chronic non-fatal plasmodium knowlesi infection. | 1982 | 7174003 | |
| long term cultivation of a simian malaria parasite (plasmodium knowlesi) in a semi-automated apparatus. | an apparatus is described and illustrated for the continuous semi-automated cultivation of plasmodium knowlesi. the change of medium was automated and involved six operations. parasites were maintained for 12 weeks, at which time the experiment ended. during this period, parasite density, morphology and serological specificity were monitored. parasites retained synchromy and normal morphology only for the first cycle in culture. the maximum degree of morphological abnormality (90%) was reached a ... | 1980 | 7210132 |
| nucleosomal organization of chromatin in plasmodium knowlesi. | 1980 | 7218104 | |
| transbilayer phospholipid asymmetry in plasmodium knowlesi-infected host cell membrane. | the membranes from normal and plasmodium knowlesi-infected rhesus monkey erythrocytes (90 to 95 percent infected with early ring stage) were analyzed for transbilayer distribution of phosphatidylcholine (pc), phosphatidylethanolamine (pe), and phosphatidylserine (ps), by means of chemical and enzymatic probes. the external monolayer of the normal red cell membrane contained at least 68 to 72 percent of the total phosphatidylcholine and 15 to 20 percent of the total phosphatidylethanolamine. in t ... | 1981 | 7233198 |
| in vitro susceptibility of erythrocytes of presbytis entellus (indian langur) to plasmodium knowlesi & blocking of merozoite invasion process by certain protease inhibitors. | 1981 | 7239571 | |
| paper chromatographic separation of phosphate esters, tricarboxylic cycle acids and amino acids in extracts from malaria parasites. | a paper chromatographic method for the separation and identification of complex mixtures of phosphate esters, tricarboxylic cycle acids and amino acids in biological extracts is described. the method has been applied to the investigation of carbohydrate metabolism pathways in the intraerythrocytic, simian malaria parasite plasmodium knowlesi; on treatment of parasitized erythrocytes with [u-c14]glucose, a perchloric acid extract was prepared and separated by chromatography on whatman 31 et filte ... | 1981 | 7276119 |
| identification of surface proteins on viable plasmodium knowlesi merozoites. | viable merozoites of plasmodium knowlesi were isolated and the proteins that were labeled on intact merozoites by lactoperoxidase-catalyzed radioiodination were identified. sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography of triton soluble extracts of labeled merozoites demonstrated eight major bands ranging in apparent molecular weight from 150,000 d to 22,000 d. exposure of intact merozoites to trypsin (10 microgram/ml) for 10 min resulted in the loss of the two hi ... | 1981 | 7277254 |
| ribonucleases & deoxyribonucleases in plasmodium knowlesi. | 1981 | 7287069 | |
| evaluation of plasmodium knowlesi antigen for serodiagnosis of human malaria infection. | 1981 | 7287093 | |
| cellular studies in rhesus monkeys during acute, protracted and reinfection stages infected with plasmodium knowlesi. | 1981 | 7287094 | |
| red cell and plasma lipids in monkeys infected with plasmodium knowlesi. | 1981 | 7287095 | |
| acid hydrolases of merozoites and other erythrocytic stages of plasmodium knowlesi. | 1981 | 7287096 | |
| presbytis entellus as a new host for experimental plasmodium knowlesi infection. | 1981 | 7287097 | |
| effect of metabolic inhibitors on in vitro intracellular development and invasion of plasmodium knowlesi. | 1981 | 7309183 | |
| rhesus monkeys protected against plasmodium knowlesi malaria produce antibodies against a 65,000-mrp. knowlesi glycoprotein at the surface of infected erythrocytes. | sera from 27 rhesus monkeys immunized in various ways against the h strain of plasmodium knowlesi were analyzed by quantitative crossed immunoelectrophoresis. the reaction of the sera was compared with a reference immune serum only reactive with p. knowlesi-specific 65,000-mr glycoprotein-immune component 13 (gp65/ic13) in membranes of infected rhesus monkey erythrocytes. triton x-100-solubilized, 125i-labeled membranes of schizont-infected erythrocytes were used as an antigen. sera from 9 or 10 ... | 1981 | 7309238 |
| analysis of proteins synthesized in vitro by the erythrocytic stages of plasmodium knowlesi. | studies were performed to identify specific parasite proteins synthesized within plasmodium knowlesi-infected rhesus erythrocytes. sodium didecyl sulphate polyacrylamide gel electrophoresis (sds-page) of whole parasites freed from the host erythrocyte by immune lysis, of membranous and cytoplasmic parasite fractions, and of isolated merozoites, detected several parasite-specific components after coomassie blue staining of the separated proteins. however, significant contamination with host eryth ... | 1980 | 7422361 |
| in vitro invasion of macaca assamensis erythrocytes by plasmodium knowlesi merozoites. | 1980 | 7429563 | |
| reduced lectin binding on erythrocytes of monkeys infected with malaria. | the number of binding sites for axinella lectin (specific for d-galactose) on monkey erythrocytes containing schizonts of plasmodium knowlesi was found to be reduced by about a third, from approximately 11 x 10(6) sites on normal erythrocytes to approximately 8 x 10(6) sites on parasitized erythrocytes. in contrast, only minor differences were found in the amounts of iodinatable external proteins. the results indicate that there is a general reduction of accessible sugars to which lectins may bi ... | 1980 | 7445041 |
| the effect of colchicine on the development of plasmodium knowlesi in vitro. | 1980 | 7469562 | |
| aspects of immunity for the ama-1 family of molecules in humans and non-human primates malarias. | the apical membrane antigen (ama-1) family of malaria merozoite proteins is characterised by a high degree of inter-species conservation. evidence that the protein (pk66/ama-1) from the simian parasite plasmodium knowlesi was protective in rhesus monkeys suggested that the 83kda p. falciparum equivalent (pf83/ama-1) should be investigated for protective effects in humans. here we briefly review pertinent comparative data, and describe the use of an eukaryotic full length recombinant pf83/ama-1 m ... | 1994 | 7565135 |
| chemokine class differences in binding to the duffy antigen-erythrocyte chemokine receptor. | the duffy blood group antigen-erythrocyte chemokine receptor has been shown to bind to chemokines of both the c-x-c and c-c classes and to the malarial parasites plasmodium vivax and plasmodium knowlesi. we performed experiments to evaluate the binding properties of this receptor for the newly appreciated "c" and "non-elr c-x-c" classes of chemokines. binding to mouse erythrocytes was also evaluated for the first time. whereas elr c-x-c and c-c chemokines bound to human erythrocytes with high af ... | 1995 | 7592697 |
| isolation of multiple sequences from the plasmodium falciparum genome that encode conserved domains homologous to those in erythrocyte-binding proteins. | open reading frames in the plasmodium falciparum genome encode domains homologous to the adhesive domains of the p. falciparum eba-175 erythrocyte-binding protein (eba-175 gene product) and those of the plasmodium vivax and plasmodium knowlesi duffy antigen-binding proteins. these domains are referred to as duffy binding-like (dbl), after the receptor that determines p. vivax invasion of duffy blood group-positive human erythrocytes. using oligonucleotide primers derived from short regions of co ... | 1995 | 7624377 |
| evolutionary relatedness of some primate models of plasmodium. | primate--and, specifically, monkey--malaria infections are commonly used for understanding the pathology of and immune response to the human disease because they are thought to resemble most closely the host-parasite relationship found in humans. plasmodium cynomolgi is used extensively as a model for the human parasite, p. vivax, and p. knowlesi is used primarily as a model for the development of erythrocytic-stage vaccines. both of these simian parasites can naturally infect man, resulting in ... | 1993 | 7689135 |
| a receptor for the malarial parasite plasmodium vivax: the erythrocyte chemokine receptor. | plasmodium vivax and p. falciparum are the major causes of human malaria, except in sub-saharan africa where people lack the duffy blood group antigen, the erythrocyte receptor for p. vivax. duffy negative human erythrocytes are resistant to invasion by p. vivax and the related monkey malaria, p. knowlesi. several lines of evidence in the present study indicate that the duffy blood group antigen is the erythrocyte receptor for the chemokines interleukin-8 (il-8) and melanoma growth stimulatory a ... | 1993 | 7689250 |
| a mutant of melanoma growth stimulating activity does not activate neutrophils but blocks erythrocyte invasion by malaria. | alanine scanning mutagenesis of the charged amino acids of melanoma growth stimulating activity (mgsa) was used to identify specific residues that are involved in binding to the human erythrocyte duffy antigen/chemokine receptor (darc) and to the type b interleukin-8 receptor (il-8rb) on neutrophils. receptor binding and biological studies with the alanine scan mutants of mgsa demonstrate that mgsa binds to darc and the il-8rb through distinct binding regions. one of the mgsa mutants, e6a, binds ... | 1995 | 7744785 |
| identification of two cysteine-rich, lipophilic proteins on the surface of plasmodium knowlesi ookinetes: pks20 and pks24. | 1994 | 7909295 | |
| dimorphism and intergenic recombination within the microneme protein (mp-1) gene family of plasmodium knowlesi. | the microneme protein-1 (mp-1) of plasmodium knowlesi and plasmodium vivax facilitates merozoite invasion of the erythrocyte by binding to duffy blood group antigens. since this protein is important in the invasion process and is a potential vaccine candidate, it is important to understand the nature of diversity within the mp-1 gene. nine mp-1 gene sequences were compared from 2 isolates of p. knowlesi and a laboratory strain of p. vivax. the mp-1 genes of p. knowlesi were dimorphic based upon ... | 1994 | 7910374 |
| staurosporine inhibits invasion of erythrocytes by malarial merozoites. | staurosporine, a protein kinase inhibitor, inhibits the invasion of rhesus by plasmodium knowlesi merozoites with an ic50 of 250 nm. the drug exerts its effects primarily on the merozoite, with little or no effect on the erythrocyte. okadaic acid, an inhibitor of protein phosphatases, can partially abrogate the inhibitory effects of staurosporine. staurosporine arrests invasion at a step which is ultrastructurally similar to the arrest caused by cytochalasins b and d: the merozoite attaches, api ... | 1994 | 7957765 |
| natural variation within the principal adhesion domain of the plasmodium vivax duffy binding protein. | the blood-stage development of malaria parasites is initiated by the invasion of merozoites into susceptible erythrocytes. specific receptor-ligand interactions must occur for the merozoites to first attach to and then invade erythrocytes. because the invasion process is essential for the parasite's survival and the merozoite adhesion molecules are exposed on the merozoite surface during invasion, these adhesion molecules are candidates for antibody-dependent malaria vaccines. the duffy binding ... | 1994 | 7960140 |
| characterization of phosphatidylinositol synthase and evidence of a polyphosphoinositide cycle in plasmodium-infected erythrocytes. | plasmodium knowlesi-infected erythrocytes possess a membranous cytidine 5'-diphospho-1,2-diacyl-sn-glycerol: myoinositol 3-phosphatidyl transferase (pi synthase) (ec 2.7.8.11) activity of 10 +/- 1.7 nmol min-1 per 10(10) infected cells. the activity was successfully solubilized with 40 mm n-octyl-beta-d-glucopyranoside in the presence of bivalent metal ions which were absolutely required for activity. the optimal ph was 8 and the apparent ks for mn2+ was 0.1 mm. mg2+ allowed two-fold higher pi s ... | 1994 | 8008017 |
| identification of the erythrocyte binding domains of plasmodium vivax and plasmodium knowlesi proteins involved in erythrocyte invasion. | plasmodium vivax and the related monkey malaria, p. knowlesi, require interaction with the duffy blood group antigen, a receptor for a family of chemokines that includes interleukin 8, to invade human erythrocytes. one p. vivax and three p. knowlesi proteins that serve as erythrocyte binding ligands in such interactions share sequence homology. expression of different regions of the p. vivax protein in cos7 cells identified a cysteine-rich domain that bound duffy blood group-positive but not duf ... | 1994 | 8046329 |
| removal of leucocytes from plasmodium vivax-infected blood. | 1994 | 8067817 | |
| generation of reactive oxygen species by blood monocytes during acute plasmodium knowlesi infection in rhesus monkeys. | the status and kinetics of monocyte activation during acute p. knowlesi infection was investigated by latex-induced, luminol-dependent chemiluminescence (cl) response. the contribution of various reactive oxygen species (ros) to cl response was estimated before infection and at peak parasitaemia (day 7 post infection) by using scavengers of ros (benzoate, catalase and superoxide dismutase). the chemiluminescence index (cli) was not found to be significantly different from controls on day 2 posti ... | 1993 | 8267953 |