The present paper reviews our recent data concerning the use of immunological methods employing monoclonal antibodies and synthetic peptides to study malaria transmission and immunity and to diagnose plasmodial infection. As concerns malaria transmission, we studied the main vectors of human malaria and the plasmodial species transmitted in endemic areas of Rondônia state, Brazil. The natural infection on anopheline was evaluated by immunoradiometric assay (IRMA) using monoclonal antibodies to an immunodominant sporozoite surface antigen (CS protein) demonstrated to be species specific. Our results showed that among six species of Anopheles found infected, An. darlingi was the main vector transmitting Plasmodium falciparum and P. vivax malaria in the immediate vicinity of houses. In order to assess the level of anti-CS antibodies we studied, by IRMA using the synthetic peptide corresponding to the repetitive epitope of the sporozoite CS protein, sera of individuals living in the same areas where the entomological survey has been performed. In this assay the prevalence of anti-CS antibodies was very low and did not reflect the malaria transmission rate in the studied areas. In relation to malaria diagnosis, a monoclonal antibody specific to an epitope of a 50 kDa exoantigen, the major component of supernatant collected at the time of schizont rupture, was used as a probe for the detection of P. falciparum antigens. This assay seemed to be more sensitive than parasitological examination for malaria diagnosis since it was able to detect plasmodial antigens in both symptomatic and asymtomatic individuals with negative thick blood smear at different intervals after a last parasitologically confirmed confirmed attack of malaria.

Alterações imunológicas na Síndrome de Imunodeficiência Adquirida em pacientes do Rio de Janeiro, Brasil. O perfil imunológico de 15 pacientes com Síndrome de Imunodeficiência Adquirida (AIDS) e 11 com Síndrome de Linfadenipatia Crônica, foram estudados. Os pacientes com AIDS mostraram reduzida percentagem de linfócitos T (CD3) totais e T auxiliares (CD4), aumento relativo no número de linfócito T-supressores (CD8) e uma marcante inversão na relação T-auxiliares/supressores (CD4/CD8). A resposta linfoproliferativa para PHA, ConA, PPD e PWN, estava diminuída. Foi também observado hipergamaglobulinemia e níveis aumentados de complexos imunes circulantes. Os pacientes com Síndrome de Linfadenopatia Crônica também mostraram importantes alterações imunológicas, mas não tão intensas como nos de AIDS. Estes dados são similares aos observados nos Estados Unidos e na Europa.

The immunoloical profile of acquired immunodeficiency syndrome (AIDS) and chronic lymphadenopathy syndrome (CLAS) in 15 and 11 Brazilian patients, respectively, was studied. The AIDS patients showed reduced percentage of total T (CD3) and T-helper-inducer (CD4) lymphocytes, relative increase in numbers of T-suppressor-cytotoxic (CD8) cells and a marked inversion of T-helper-inducer/suppressor-cytotoxic (CD4/CD8) ratio. Lymphoproliferative responses to PHA, ConA, PPD and PWM were diminished. Hypergamaglobulinemia and high levels of circulating immune complexes were also found. The CLAS patients also showed important immunological alterations, but not so intense as those with AIDS. These data seems to be similar to those observed in other parts of the world.