Antiretroviral drug resistance in HIV-2: three amino acid changes are sufficient for classwide nucleoside analogue resistance

Genotypic surveys suggest that human immunodeficiency virus type 1 (HIV-1) and HIV-2 evolve different sets of mutations in response to nucleoside reverse-transcriptase inhibitors (NRTIs). We used site-directed mutagenesis, culture-based phenotyping, and cell-free assays to determine the resistance profiles conferred by specific amino acid replacements in HIV-2 reverse transcriptase. Although thymidine analogue mutations had no effect on zidovudine sensitivity, the addition of Q151M together with K65R or M184V was sufficient for high-level resistance to both lamivudine and zidovudine in HIV-2, and the combination of K65R, Q151M, and M184V conferred classwide NRTI resistance. These data suggest that current NRTI-based regimens are suboptimal for treating HIV-2 infection.

Human immunodeficiency virus types 1 and 2 exhibit comparable sensitivities to Zidovudine and other nucleoside analog inhibitors in vitro

Using an indicator cell assay that directly quantifies viral replication, we show that human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2, respectively) exhibit similar sensitivities to 3'-azido-3'-deoxythymidine (zidovudine) as well as other nucleoside analog inhibitors of reverse transcriptase. These data support the use of nucleoside analogs for antiviral therapy of HIV-2 infection.