J. Exp. Med. doi:10.1084/jem.20091933 (2009)

The antiviral enzyme APOBEC3G inhibits HIV infection by causing damaging genetic mutations in replicating viruses. Arnaud Moris of the Pasteur Institute in Paris and his colleagues now demonstrate that this enzyme also combats HIV by triggering the activation of the immune system's cytotoxic T cells, which kill helper T cells infected with HIV.

Moris and his co-workers showed in vitro that HIV particles harbouring APOBEC3G are more effective activators of HIV-specific cytotoxic T cells than viruses lacking the enzyme. Mutating the enzyme's active site eliminated this effect.