Assuntos
Infecções Oportunistas Relacionadas com a AIDS/imunologia , Soropositividade para HIV/imunologia , Malária Falciparum/imunologia , Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adolescente , Adulto , Animais , Anticorpos Antiprotozoários/análise , Western Blotting , Brasil/epidemiologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Anticorpos Anti-HIV/análise , Soropositividade para HIV/diagnóstico , Soropositividade para HIV/epidemiologia , Humanos , Malária Falciparum/diagnóstico , Malária Falciparum/epidemiologia , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/imunologia , Reação em Cadeia da Polimerase/métodosRESUMO
The study evaluated six Plasmodium falciparum antigen extracts to be used in the IgG and IgM enzyme-linked immunosorbent assays (ELISA), for malaria diagnosis and epidemiological studies. Results obtained with eighteen positive and nine negative control sera indicated that there were statistically significant differences among these antigen extracts (Multifactor ANOVA, p < 0.0001). Urea, sodium deoxycholate and Zwittergent antigen extracts performed better than did the three others, their features being very similar for the detection of IgG antibodies. Urea, alkaline and sodium deoxycholate antigen extracts proved to be better than the others for the detection of IgM antibodies. A straight line relationship was found between the optical densities (or their respective log10) and the log10 of antibody dilutions, with a very constant slope. Thus serum titers could be determined by direct titration and by two different equations, needing only one serum dilution. For IgM antibody detections, log10 expression gave results that better correlated with direct titration (95% Bonferroni). For IgG antibody detections, the titer differences were not significant. The reproducibility of antibody titers and antigen batches was also evaluated, giving satisfactory results.