Molecular basis for vaccine development against the ehrlichial pathogen Anaplasma marginale.

Anaplasma marginale is a tick-transmitted ehrlichial pathogen causing severe morbidity and mortality in livestock on six continents. Development of safe effective vaccines would be greatly facilitated by identification of the protective immune mechanisms and by understanding how the pathogen evades immune effectors to establish persistent infection. In this article, Guy Palmer and colleagues review recent progress in identifying how defined epitopes induce protective immunity and the role of antigenic variation in these epitopes as a mechanism of persistence.