Abstract

The diversity of antigens on the surface of Plasmodium falciparum-infected red blood cells is likely a crucial target for naturally acquired immunity against malaria. In response to natural infections, antibodies that cause agglutination are triggered specifically by the variant surface antigen (VSA) expressions of the infecting parasites. Previous examinations involving diverse parasite isolates exposed to heterologous plasma from Kenyan children revealed a highly variable proportion of plasma inducing agglutination, indicating the presence of both rare and common variants. In this context, the agglutination factor (AF) of 115 isolates from Kenyan children was assessed. The findings demonstrated a notable elevation in AF for isolates causing severe malaria compared to those causing mild malaria. Additionally, AF substantially decreased as the age of the infected child increased. We propose that parasites responsible for severe illness tend to express a specific subset of VSA variants that are particularly associated with infections in children with limited immunity.