Host factors in HIV-1 replication: The good, the bad and the ugly

The ability of HIV-1 to replicate in its target cells is influenced by numerous host factors that act on different steps of the viral replication cycle. The effects of these host factors on the replication cycle can be cell type specific and they can either support or restrict viral replication. Recent studies suggest that there is a third group of host factors that play a more intricate role. In first instance these factors seem to have a restrictive effect on replication but when the bigger picture is taken into account, these factors actually allow HIV-1 to evade the innate immune response and thus act in a pro-viral manner. Booiman and colleagues have studied the effect of several novel and known host factors on HIV-1 replication and pathogenesis. Their results provide new insights in the complex interplay between HIV-1 and its host and will contribute to the development of future therapies to stop the ongoing HIV-1 pandemic.