Molecular cloning of the human immunodeficiency virus subtype 2 strain HIV-2UC2.

An infectious molecular clone was derived from the HIV-2UC2 isolate that previously was found to persistently infect and induce an AIDS-like disease syndrome in baboons. The molecularly cloned virus (HIV-2UC2mc) showed in vitro properties similar to those of the parental isolate with regard to T-cell tropism, cytopathicity, and the ability to infect primary baboon PBMC. Nevertheless, when inoculated into two baboons, the cloned virus showed a limited ability to replicate in these animals. DNA sequence analysis revealed a defective vpr gene in the UC2mc as well as in the pathogenic parental UC2 strain. Thus, the vpr gene is not required for the induction of disease in baboons. The attenuated infectious molecular clone of UC2 should be useful for future studies designed to map the genetic determinants of HIV-2 pathogenesis in the baboon model and to evaluate vaccine strategies.