Association of malaria with inactivation of alpha1,3-galactosyl transferase in catarrhines.

Present-day catarrhines (old world monkeys and hominoids) lack Gal alpha1-3 Gal beta1-4 GlcNAc-R structures (alpha-galactosyl epitopes) and produce the corresponding anti-galactosyl antibodies (anti-gal), while platyrrhines (new world monkeys) and non-primate mammals possess alpha-galactosyl epitopes and lack anti-gal. Anti-gal is shown to inhibit Plasmodium falciparum growth in culture in a concentration dependent manner. probably by binding to alpha-galactosyl epitopes on merozoite surface molecules and causing complement mediated damage. A P. falciparum-like malaria parasite may therefore have selected for the inactivation of an alpha 1-3 galactosyl transferase in catarrhines. The implications of the results for the development of clinical immunity to falciparum malaria are briefly discussed.