In vitro growth inhibition of Plasmodium falciparum by sera from tropical splenomegaly syndrome patients.

Sera from tropical splenomegaly syndrome (TSS) and non-TSS patients from the same village were examined for their ability to inhibit the in vitro growth of Plasmodium falciparum. Using synchronized malaria cultures, sera from both groups inhibited parasite development only if added before merozoite reinvasion of erythrocytes had occurred. There was no significant difference in the degree or apparent mechanism of inhibition caused by TSS and non-TSS sera. These results suggest that the aberrant immune response that results in TSS may not be associated with the elaboration of unique serum factors that differentially inhibit growth of the parasite in vitro.