Cellular and antibody responses to the Plasmodium falciparum heat shock protein Pf72/HSP70 during and after acute malaria in individuals from an endemic area of Brazil

Abstract

Proliferative and antibody responses to three synthetic peptides corresponding to Pf72/HSP70 were followed-up in acute malaria patients from an endemic area of Brazil. In vitro lymphocyte responsiveness to all peptides was relatively low and short-lived and there was a considerable variation in the frequency and magnitude of the individual lymphoproliferative response to the peptides at different periods after the onset of infection. Although 96% of the patients had IgG antibodies to crude Plasmodium falciparum asexual blood stage antigens, specific IgG antibody responses to the peptides varied from 12.5 to 40% according to the tested peptides. No significant difference was observed in the proliferative or antibody responses to the peptides between individuals that remained parasitemic after treatment and those that recovered from malaria infection. The different frequencies of proliferative responses in peripheral blood T cells on different occasions after the onset of their infection show that, in order to be informative, evaluation of the in vitro cellular immune response to peptides requires longitudinal studies in which each individual is tested repeatedly.