The in vivo dynamics of antigenic variation in Trypanosoma brucei

Abstract

Trypanosomes reveal tricky tricks in vivo The sleeping sickness parasite, Trypanosoma brucei , is covered with variant surface glyco proteins (VSGs) recognized by the host's immune system. The parasite uses a repertoire of 2000 VSG genes to switch between different surface variants, continually evading the host's defensive responses. Classic experiments showed that one variant succeeded another, causing waves of infection; however, infection in animals shows different behavior. Mugnier et al. discovered that several VSGs are expressed simultaneously and that the repertoire for variation is amplified even more by recombination between the genes to make mosaic VSGs. Science , this issue p. 1470