Exploiting the natural history of cytomegalovirus to vaccinate against HIV.

The quest for a HIV vaccine that prevents HIV infection remains an ongoing struggle after failures of candidate vaccines in clinical trials. The threshold for a HIV vaccine is enormous. Vaccine-stimulated immunity must restrict HIV replication to the mucosal surface and prevent any systemic spread. A recent study at the Oregon National Primate Research Center (OR, USA) involving the SIV/rhesus macaque model of HIV demonstrates that it is possible to elicit protective immunity to repeated rectal exposure of virulent SIV. Together with other rhesus macaque studies, the results offer a paradigm for vaccine protection against the sexual transmission of HIV.