MALARIA CELLULAR IMMUNE-RESPONSES IN NEONATES FROM CAMEROON

T cell responses to leucoagglutinin, PPD, and seven Plasmodium falcipa rum blood stages antigens were investigated in 164 cord blood samples from Cameroonian neonates. In vitro T cell responses were measured by lymphocyte proliferation, and IL-2, IFN-gamma, and IL-4 release in the presence of crude schizont extract, purified Pf155/RESA protein, and synthetic peptides from Pf155/RESA. Following culture in presence of l eucoagglutinin or PPD, proliferation and cytokine production were very low, as compared to adults from the same area. Interestingly, followi ng stimulation of cold blood lymphocytes by malaria antigens, the perc entage of responders and the mean level of positive responses were of the same order tl?nn those observed in adults for IL-2 production, whi le proliferative and IL-4 responses were only marginally decreased. Co nversely, IFN-gamma production was highly reduced, as compared to adul ts. Our results demonstrate that prenatal immune priming to malarial a ntigens is common in this al ea and that the fetal immune system is ab le to respond to antigenic stimuli, as cells proliferate and generate cytokines. As cord blood lymphocytes may be induced to differentiate i nto effector cells producing predominantly Th1 or Th2 cytokines, malar ia during pregnancy might direct the functional capacity of fetal T ce lls to respond to further infection.