This review describes some of the virus-cell relationships that might contribute to the state of latency observed in HIV infection. Viruses use many mechanisms to persist in their host, and the molecular interactions evoked by the virus and the cell on each other can influence the outcome of an infection. The topics of cellular effects on the virus versus viral effects on the cell are discussed in the context of viral life-cycle, activation and defective viruses, as well as latency concepts in relation to in vivo findings and in vitro cell models.