Differential Maintenance of the M184V Substitution in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 by Various Nucleoside Antiretroviral Agents in Tissue Culture

Abstract

The M184V substitution in human immunodeficiency virus type 1 reverse transcriptase (RT) is rapidly selected in tissue culture following serial passage of wild-type virus in the presence of increasing concentrations of lamivudine (3TC). M184V is also associated with several alterations of RT enzymatic function in vitro that may adversely affect viral fitness or replication capacity, which creates a potential rationale for its maintenance once it has been selected by antiviral chemotherapy. However, the relative effectiveness of nucleoside RT inhibitors that are structurally unrelated to 3TC in selecting and/or maintaining M184V has not been investigated. In the present study, we have studied the abilities of a variety of drugs, i.e., zalcitabine (ddC), didanosine (ddI), abacavir (ABC), and the novel nucleoside SPD754, in addition to 3TC, to maintain the presence of M184V in tissue culture and have shown that SPD754, ABC, and 3TC are able to preserve M184V in mixed dual infections consisting of wild-type viruses and clinical isolates which contained the M184V mutation. Moreover, M184V could also be maintained in these cultures when a subtherapeutic concentration of 3TC (i.e., 0.05 M) was used. In contrast, neither ddI nor ddC was able to maintain M184V to the same extent as the other drugs after 10 weeks of tissue culture in mixtures of wild-type viruses and isolates containing M184V in different proportions.

Human Immunodeficiency Virus Type 1: Resistance to Nucleoside Analogues and Replicative Capacity in Primary Human Macrophages

“…Thus, using cells with a remarkably low dNTP content, mutations that did not appear to reduce HIV-1 RC in cells with high DNA turnover were found to have a strong impact on viral RC. This phenomenon confirms the findings of a number of different previous studies, which documented the effect of a lowdNTP environment on reduced HIV replication or reduced RT processivity, mostly in the context of the M184V mutation (9,10,14,15,45,55,63,66). Although an early study by Caliendo et al (16) documented that a four-TAM mutant displayed increased processivity in vitro under limited dNTP levels, our results confirm recent findings by Bouchonnet et al (14) that reduced efficiency of DNA synthesis by mutant RT in the presence of low dNTP concentrations, which may involve enzymatic properties other than enzyme processivity, is not restricted to the M184V mutation.…”

The Connection Domain Mutation N348I in HIV-1 Reverse Transcriptase Enhances Resistance to Etravirine and Rilpivirine but Restricts the Emergence of the E138K Resistance Mutation by Diminishing Viral Replication Capacity

“…As controls, all viruses were simultaneously passaged without drugs. Reverse transcriptase assays were performed, as described previously, to monitor viral replication (37,38,58,59). Based on the ratio of the RT value of control wells (100%) to those of wells containing drug at the previous round of replication, drug concentrations were adjusted at subsequent passages.…”

Characterization of the E138K Resistance Mutation in HIV-1 Reverse Transcriptase Conferring Susceptibility to Etravirine in B and Non-B HIV-1 Subtypes

“…As controls, all viruses were simultaneously passaged without drugs. RT assays were performed weekly as described to monitor viral replication (26,35). Based on the ratio of the RT value in culture fluids of control wells to wells with drug at the previous round of replication, drug concentrations were increased at subsequent passages.…”