A genotypic analysis of patients receiving Zidovudine with either Lamivudine, Didanosine or Zalcitabine dual therapy using the LiPA point mutation assay to detect genotypic variation at codons 41, 69, 70, 74, 184 and 215

Background: The Murex-Innogenetics LiPA HIV-1 RT assay can be used to identify the presence of mutations of the reverse transcriptase gene at codons 41, 69, 70, 74, 184 and 215 of HIV-1, which have been shown to confer resistance to the nucleoside analogs Zidovudine (ZDV), Lamivudine (3TC), Didanosine (ddI) and Zalcitabine (ddC). The M184V mutation of the reverse transcriptase gene of HIV-1 has been associated with resistance to 3TC, ddC and ddI. This mutation has also been observed in patients receiving ZDV ddC and ZDV ddI. We used LiPA HIV-1 RT assay to identify the presence of either consensus methionine 184 or the mutant valine 184 with three groups of patients who were treated with ZDV:3TC, ZDV:ddI or ZDV:ddC combination therapy. Objecti6es: The aim of our study was to determine the viral genotype of patients who were considered to be failing therapy, by two ways: using sequencing and LiPA assays. In particular we were interested in establishing a possible correlation between these methods. Study design: The study group consisted of a consecutive series of 33 patients with a treatment failure, 18 of whom received ZDV 3TC therapy, seven received ZDV ddI and eight received ZDV ddC therapy. We also examined a small cohort of seven seroconverters. Results: The M184V mutation was observed in 47.0% of patients receiving ZDV 3TC combination therapy but was not observed in either patient group receiving either ddI or ddC as co-therapy with ZDV. There was no evidence of the L74V mutation in our study group in either the ZDV:ddI or ZDV:ddC combination therapy group. We found the frequency of the K70R mutation to be higher in patients treated with ZDV:ddI (P 0.033) or ZDV:ddC (P 0.3) when compared with patients treated with ZDV:3TC. Conclusion: The LiPA assay allowed for the rapid detection of wild type and amino acid variations at key positions conferring resistance to the most used antiviral RT inhibitors. This represented a rapid, quite sensitive, and simple genotyping test. For these reasons the LiPA assay proved to be useful in studying genetic resistance in large screenings, when key RT mutations could be useful in guiding an effective HIV-1 suppressing regimen

Aminooxypentane-RANTES, an inhibitor of R5 human immunodeficiency virus type 1, increases the interferon gamma to interleukin 10 ratio without impairing cellular proliferation

Studies have demonstrated that the beta-chemokines RANTES, MIP-1 alpha, and MIP-1 beta suppress human immunodeficiency type 1 (HIV-1) replication in vitro, Infection with HIV-1 requires expression of CD4 antigen and the chemokine receptor CXCR4 (X4) or CCR5 (R5) on the surface of target cells. The engagement of these receptors with the viral surface proteins is essential for the membrane fusion process. This study investigated the anti-HIV-1 activity of a derivative of RANTES, the CCR5 antagonist aminooxypentane (AOP)-RANTES, on R5 HIV-1 isolates in peripheral blood mononuclear cells, In drug exposure experiments, AOP-RANTES efficiently inhibited viral replication of HIV-1 R5 strains, with a viral breakthrough observed after the withdrawal of the compound, The HIV-1-specific proliferative capacity was maintained under all conditions when compared with controls, An increase in IFN-gamma production accompanied by a parallel decrease in the generation of IL-10 was observed following the in vitro exposure of cells to AOP-RANTES in the presence of three of four HIV-1 R5 isolates. These experiments confirmed that the chemokine receptor antagonist AOP-RANTES was effective as an inhibitor of HIV-1 R5 strain infectivity in peripheral blood mononuclear cells, The capacity of this compound to maintain HIV-1-specific proliferative activity with a shift toward a type 1 cytokine profile makes this compound a unique molecule, one adopting an immunological pathway to limit HIV-1 infection

In vitro inhibition of HIV-1 by Met-SDF-1beta alone or in combination with antiretroviral drugs

Compounds that can block the CXCR4 chemokine receptor are a promising new class of antiretroviral agents. In these experiments we studied the effect of a modified form of the native stromal cell-derived factor-1 (SDF-1), Met-SDF-1beta. The in vitro susceptibility of two different CXCR4-tropic HIV-1 strains was determined. Antiviral effect was assessed by the reduction of p24 antigen production in PHA-stimulated peripheral blood mononuclear cells with exposure to the modified SDF-1 molecule. The 50% inhibitory concentrations (IC50) were derived from six separate experiments. The IC50 against the two HIV-1 isolates was in 1.0-2.8 microg/ml range for Met-SDF-1beta. Met-SDF-1beta showed synergy to additivity with either zidovudine or nelfinavir at IC75 IC90 and IC95. Additivity was seen when Met-SDF-1beta was combined with efavirenz. No cellular toxicity was observed at the highest concentrations when these agents were used either singly or in combination. This compound is a promising new candidate in a receptor-based approach to HIV-1 infection in conjunction with currently available combination antiretroviral drug therapies

Combination of CCR5 and CXCR4 Inhibitors in Therapy of Human Immunodeficiency Virus Type 1 Infection: In Vitro Studies of Mixed Virus Infections

We studied the combined anti-human immunodeficiency virus type 1 (HIV-1) effects of a derivative of stroma-derived factor 1β (SDF-1β), Met-SDF-1β, and a modified form of RANTES, aminooxypentane (AOP)-RANTES. The antiviral agents were tested singly or in combination at 95 and 99% virus inhibitory concentrations. Clinical R5 and X4 HIV-1 isolates were used. AOP-RANTES inhibited R5 but not X4 viruses, whereas Met-SDF-1β had the opposite effect. Combinations of these compounds inhibited mixed infections with R5 and X4 viruses (95 to 99%), whereas single drugs were less inhibitory (32 to 61%). Combinations of R5 and X4 inhibitors are promising and deserve further evaluation