Biological and genetic characterization of a human immunodeficiency virus strain resistant to CXCR4 antagonist t134

The chemokine receptors CXCR4 and CCR5 are considered to be potential targe ts for the inhibition of HIV-1 replication. We have reported that T134 and T140 inhibited X4 HIV-I infection specifically because they acted as CXCR4 antagonists. In the present study, we have generated a T134-resistant virus (trHIV-1(NL4-3)) in a cell culture with gradually increasing concentration s of the compound. The EC50 of T134 against trHIV-1(NL4-3) recovered after 145 passages was 15 times greater than that against wild-type HIV-1(NL4-3). This adapted virus was resistant to other CXCR4 antagonists, T140, AMD3100 , and ALX40-4C, and SDF-1; from 10 to 145 times greater than that against w ild-type HIV-1(NL4-3). On the other hand, T134, T140, and ALX40-4C were sti ll active against AMD3100-resistant viruses (arHIV-1(018A)). The triHIV-1(N L4-3) contained the following mutations in the V3 loop of gp120: N269K, Q27 8T, R279K, A284V, F285L, V286Y, I288T, K290E, N293D, M294I, and Q296K; an i nsertion of T at 290; and Delta 274-275 (SI). In addition, many other mutat ions were recognized in the V1, V2, and V4 domains. Thus, resistance to T13 4 may be the consequence of amino acid substitutions in the envelope glycop rotein of X4 HIV-1. The trHIV-1NL4-3 could not Utilize CCR5 as an HIV infec tion coreceptor, although many amino acid substitutions were recognized. Th e trHIV-1(NL4-3) acquired resistance to vMIP II, which could inhibit both X 4 and R5 HIV-I infection. However, neither the ligands of CCR5, RANTES, and MIP-1 alpha, nor a CCR5 low molecular antagonist, TAK-779, were able to in fluence the infection of trHIV-1(NL4-3) Those results indicated that altern ation of coreceptor usage of trHIV-1(NL4-3) was not induced.