Opsonizing and agglutinating antibodies against Plasmodium falciparum schizont-infected erythrocytes in Gambian sera.

The presence of an IgG antibody to autologous schizont-infected red blood cells (SIRBC) in the sera of Gambian children with acute malaria and a positive direct anti-globulin test (DAT) was demonstrated by two methods: IgG quantitation using 125I-labelled anti-IgG and phagocytosis of these SIRBC. A similar antibody could not be demonstrated in sera of children with acute malaria and a negative DAT. When a laboratory strain of parasite was used there was a more variable pattern of IgG uptake but the highest was from sera of immune adult Gambians and Gambian children with acute malaria and a positive DAT. The uptake of IgG by SIRBC may be a useful test to determine the specificities of antibodies against different isolates of P. falciparum.