Persistence of mutations during replication of an HIV library containing combinations of selected protease mutations.

摘要

It has been known that, in some cases, accumulation of specific mutations in HIV-1 protease leads to multi-protease inhibitor (PI) resistance. We examined the persistence of mutations detected in HIV-1 clinical isolates cross-resistant to the current PIs using an HIV-1 protease restricted library (HXB2 protease in an HIV-1(NL4-3) background) in the absence of protease inhibitors. The virus library contained combinations of 0-11 amino acid substitutions (4,096 possible combinations) in the protease-encoding region. We examined the frequency of each amino acid substitution in the library using a T cell line, MT-2. The frequency of the amino acid substitutions V82T/I and L90M decreased rapidly with a short half life (t(1/2) < 10 days). However, the mutations M36I, M46I and I84V were relatively persistent: t(1/2) = 34.2, 28.1 and 30.6 days, respectively. Other amino acid substitutions, i.e., L10I, I54V, L63P, A71V and V82A, were well retained (t(1/2) > 36 days). By contrast, the half lives (t(1/2)) of the D30N and N88D mutations associated with nelfinavir (NFV) resistance were only 7.2 and 1.8 days, respectively. These results indicate that this type of the HIV-1 protease restricted library is useful to evaluate the persistence of PI resistance-associated mutations in the absence of drug selective pressure.