Disruption of antigenic variation is crucial for effective parasite vaccine

Giardia lamblia is a major intestinal pathogen causing acute or chronic diarrhea. It is thought to evade the immune system by switching its expression of the variant-specific surface protein (VSP), resulting in antigenic variation. Rivero et al. now report that by interfering with the machinery that restricts VSP expression, they can subvert antigenic variation and generate trophozoites that simultaneously express many VSPs and induce broadly reactive immunity against infection with various G. lamblia isolates.