Mice that carry several key parts of the human immune system replicate the human immune response to HIV. The model could be used to test HIV vaccine candidates — an effort that has been hindered by the lack of a suitable small-animal model.

'BLT' mice are engrafted with human bone-marrow cells, liver and thymus tissue, and produce a functional human immune system, including a robust population of human CD4+ T cells, the target of HIV. Todd Allen of the Ragon Institute in Charlestown, Massachusetts, and his colleagues show that, during the acute phase of infection, these mice generate HIV-specific killer T cell responses that closely resemble those in humans. Importantly, the virus rapidly evolves to escape these responses, just as it does in humans. What's more, BLT mice that express HLA-B57, a human gene variant that protects against HIV, show better control of HIV replication — just as humans with this variant do.

Sci. Transl. Med. 4, 143ra98 (2012)