In Vitro Selection and Characterization of Human Immunodeficiency Virus Type 2 with Decreased Susceptibility to Lopinavir

Lopinavir (LPV)-ritonavir has demonstrated durable antiviral activity in human immunodeficiency virus type 1 (HIV-1)-infected antiretroviral-naïve and protease inhibitor (PI)-experienced patients. However, information on LPV activity against HIV-2 and the patterns of mutations in HIV-2 in response to selection by LPV is limited. The activity of LPV against three strains of HIV-2 was assessed and compared to activity against a reference HIV-1 strain. LPV demonstrated activity similar to that observed against HIV-1 in two HIV-2 strains (HIV-2MSand HIV-2CBL-23) tested. On the other hand, approximately 10-fold-reduced susceptibility was observed with the third HIV-2 strain, HIV-2CDC310319. Passage of HIV-2MSwith increasing concentrations of LPV selected mutations V47A and D17N in the HIV-2 protease gene. The introduction of both 17N and 47A either individually or together into HIV-2RODmolecular infectious clones showed that the single V47A substitution in HIV-2 resulted in a substantial reduction in susceptibility to LPV. In contrast, this mutant retained wild-type susceptibility to other PIs and appeared to be hypersusceptible to atazanavir and saquinavir.