RESUMO
An antigen, designated here as the parasitized erythrocyte membrane antigen (PEMA), is present in the erythrocyte membrane surrounding all intraerythrocytic stages of Plasmodium brasilianum. An antibody specific for PEMA appeared in 21 (50%) of 42 antisera from Saimiri sciureus monkeys naturally infected with P. brasilianum. Of these 42 sera, nine (21.4%) contained antibody to the ring-infected erythrocyte membrane antigen (RESA); of these nine sera, six did not react with PEMA. Sera of humans infected with P. malariae reacted with PEMA and RESA in a similar pattern; i.e., of 83 antisera, 71 (85.5%) reacted with PEMA and 30 (36%) reacted with RESA. Only one of these latter 30 sera were not reactive with PEMA. Of 167 sera from humans infected with P. falciparum but not P. malariae, 133 (79.6%) reacted with RESA; of these, 43 (25.7% of the total) reacted with PEMA but not RESA. Although PEMA was demonstrated with P. brasilianum and RESA with P. falciparum, neither PEMA or RESA could be demonstrated with P. malariae. Interactions of PEMA and RESA and the corresponding antibodies offer a method whereby the two morphologically similar quartan species, P. malariae and P. brasilianum, can be readily distinguished from each other and may furnish clues to genetic separation of the two and the mechanisms of interaction of quartan malaria and P. falciparum where they are coendemic.
Assuntos
Antígenos de Protozoários/imunologia , Membrana Eritrocítica/imunologia , Eritrócitos/parasitologia , Plasmodium falciparum/imunologia , Plasmodium/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/análise , Antígenos de Superfície/imunologia , Reações Cruzadas/imunologia , Membrana Eritrocítica/parasitologia , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Malária/imunologia , Malária/veterinária , Malária Falciparum/imunologia , Doenças dos Macacos/imunologia , Plasmodium/classificação , Plasmodium falciparum/classificação , Plasmodium malariae/classificação , Plasmodium malariae/imunologia , SaimiriRESUMO
The new-world monkeys Saimiri sciureus (squirrel monkeys) are currently used as a model to test the efficacy of vaccines against human malaria. To improve our knowledge on this model, we tested the susceptibility of S. sciureus B cells to Epstein-Barr virus (EBV) infection. B-lymphoblastoid cell lines were obtained from six of six healthy animals after infection with the B95-8 source of EBV. The frequency distributions of spleen B cells clonally committed to the production of immunoglobulins M and G, as measured by limiting dilution analysis, were from 1 in 179 to 1 in 1,085 and from 1 in 45 to 1 in 60, respectively, in three monkeys naturally infected with Plasmodium brasilianum. In the same three animals, the frequency of spleen B cells committed to the production of P. brasilianum-specific antibody ranged from 1 in 2,211 to 1 in 9,099. One B-lymphoblastoid cell line producing anti-P. brasilianum-specific antibody was cloned twice, and the immunoglobulin G produced was purified. This monoclonal antibody recognized a parasite component of 197 kDa and was specific for Plasmodium malariae and P. brasilianum parasites. These data document that squirrel monkey B cells naturally primed by an infectious agent can be efficiently used to produce monospecific antibodies against the infectious agent.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antiprotozoários/imunologia , Linfócitos B/imunologia , Malária/imunologia , Plasmodium/imunologia , Saimiri/imunologia , Animais , Antígenos de Protozoários/química , Antígenos de Protozoários/imunologia , Linfócitos B/microbiologia , Western Blotting , Transformação Celular Viral , Herpesvirus Humano 4 , Imunoglobulina G/biossíntese , Imunoglobulina M/biossíntese , Peso Molecular , Proteínas de Protozoários/química , Proteínas de Protozoários/imunologiaRESUMO
The ring-infected erythrocyte surface antigen (RESA) of Plasmodium falciparum (RESA-P), found in the membrane of erythrocytes infected with young asexual stages of P. falciparum, is a promising vaccine candidate. Antibodies to RESA-P were inducible by infection with another human malaria species, P. malariae. Of 298 serum samples from inhabitants of three isolated localities in Peru where P. vivax and P. malariae were endemic and P. falciparum had never been reported, 26% had anti-RESA-P antibodies as evidenced by a modified immunofluorescent-antibody assay and confirmed by Western blot (immunoblot) analysis. These seroepidemiologic observations were corroborated by the fact that of six chimpanzees infected with P. malariae, three developed anti-RESA-P antibodies after infection. The modified immunofluorescent-antibody-reactive antibodies, purified by adsorption and elution on monolayers of glutaraldehyde-fixed and air-dried P. falciparum-infected erythrocytes, reacted in an immunofluorescent-antibody assay with both parasite structures and erythrocyte membrane in P. falciparum antigen preparations, but only with parasite structures in P. malariae antigen preparations. This serologic cross-reactivity between P. falciparum and P. malariae is of interest in view of the importance of RESA-P as a vaccine candidate and because the two species are coendemic in many areas.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/imunologia , Antígenos de Superfície/imunologia , Malária/imunologia , Plasmodium falciparum/imunologia , Plasmodium malariae/imunologia , Proteínas de Protozoários , Animais , Reações Cruzadas , Imunofluorescência , Humanos , Técnicas de Imunoadsorção , Peso Molecular , Pan troglodytes , PeruRESUMO
Serum samples from 460 patients with existing or previous Plasmodium infections, high antimalarial antibody titres, and no apparent risk of exposure to human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) were assayed for HTLV-III/LAV antibody; only 1 sample, from a 21-year-old African woman, was strongly reactive by enzyme-linked immunosorbent assay (ELISA) and positive by western blot. Conversely, no sample from 100 HTLV-III/LAV-positive American homosexual men was strongly reactive for antibodies to the four Plasmodium species that infect human beings by an indirect fluorescent antibody technique, or for antibodies to Plasmodium falciparum by an ELISA technique. Thus, exposure to Plasmodium does not result in HTLV-III/LAV seropositivity, and HTLV-III/LAV antibodies are not strongly cross-reactive with malarial antigens.
Assuntos
Anticorpos Antivirais/imunologia , Anticorpos/imunologia , Plasmodium/imunologia , Síndrome da Imunodeficiência Adquirida/imunologia , Adolescente , Adulto , África , Criança , Pré-Escolar , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Anticorpos Anti-HIV , Homossexualidade , Humanos , Lactente , Malária/imunologia , Masculino , Pessoa de Meia-Idade , América do Sul , Estados UnidosRESUMO
Sera from 32 patients who became ill after jungle combat training were tested for antibodies to Toxoplasma gondii using the indirect immunofluorescence test. Swift rises of both IgG and IgM antibodies occurred within 2 weeks of infection. Reduction in IgM titers, due to competitive suppression by IgG antibody, occurred in most but not all cases. Suppression of IgM reaction by IgG antibody could be prevented by adsorption of serum with Staphylococcus aureus containing protein A. Antibody of the IgM class could be detected at greater than or equal 1:256 level in many sera at 6-month and 1-year intervals after exposure. In groups with exposures such as were experienced in this study, the presence of IgM antibody titers in single serum specimens cannot be used to indicate recent exposure. Both IgG and IgM antibody may rise together to high levels very rapidly after infection; IgM did not precede IgG antibody in our 32 subjects.
Assuntos
Surtos de Doenças , Imunoglobulina G/análise , Imunoglobulina M/análise , Toxoplasmose/epidemiologia , Adolescente , Adulto , Antígenos de Protozoários/análise , Imunofluorescência , Humanos , Masculino , Panamá , Staphylococcus aureus/imunologia , Toxoplasma/imunologia , Toxoplasmose/imunologia , Toxoplasmose/transmissãoAssuntos
Malária/epidemiologia , Adolescente , Adulto , Anticorpos/análise , Sangue/parasitologia , Criança , Pré-Escolar , Humanos , Lactente , Malária/imunologia , Malária/prevenção & controle , Mineração , Peru , Plasmodium vivax/imunologia , MigrantesRESUMO
Polar staining (PS) of Toxoplasma gondii in the indirect immunofluorescence test has been considered a nonspecific reaction caused exclusively by certain immunoglobulin M (IgM) antibodies and confined to the anterior end of the parasite. After we observed a patient with positive serology for Chagas' disease who presented an IgG PS reaction, we studied sera from 120 patients with Chagas' disease, 20 sera from patients with Leishmania donovani infection, and 30 sera from patients with Leishmania braziliensis infection. When only those specimens having no detectable anti-Toxoplasma activity were considered, a significantly (P less than 0.01) higher prevalence of IgG PS was found in the Chagas' disease and L. donovani groups than in sera from normal American and Brazilian adults. Those sera also showed higher PS titers (1:64 to 1:1,024) when compared with controls (1:16 to 1:64). IgG PS titers did not decrease after serum treatment with 2-mercaptoethanol. However, the same treatment removed completely IgM PS. IgG PS, but not IgM PS, could be removed by adsorption with Trypanosoma cruzi epimastigotes. IgM PS was found in all samples studied, except in 41 of a group of 43 umbilical cord sera. It was found that the antigen source and the microscopy system can influence the detection of PS. It is proposed that after finding an intense IgG PS reaction, the laboratory should screen such serum also for anti-T. cruzi antibodies which may be undetected in the sample.