Development of resistance to VIR-353 with cross-resistance to the natural HIV-1 entry virus inhibitory peptide (VIRIP)

• DOI: 10.1097/qad.0b013e328348a733
• Publication Date: 2011-05-13T09:29:30Z
• Authors: Emmanuel Gonzalez; Ester Ballana; Bonaventura Clotet; José A. Esté
• Keywords: 0301 basic medicine; fusion; fusion inhibitor; HIV Envelope Protein gp120; Virus Internalization; gp41; HIV Envelope Protein gp41; Peptide Fragments; 3. Good health; resistance; 03 medical and health sciences; HIV Fusion Inhibitors; alpha 1-Antitrypsin; Drug Resistance, Viral; HIV-1; Mutagenesis, Site-Directed; fusion peptide; Humans

Virus-inhibitory peptide (VIRIP) has been identified as a component of human hemofiltrate that blocks HIV-1 gp41-dependent fusion by interacting with the fusion peptide. A VIRIP analogue (VIR-576) has been shown to be effective in a phase I/II clinical trial. We have evaluated the activity and mechanism of HIV-1 resistance to VIRIP and its analogue, VIR-353.Anti-HIV activity and passage of HIV-1 strains in cell culture were used to generate and identify mutations that confer resistance to VIRIP and VIR-353. Recombinant viruses harboring the most relevant mutations were generated and characterized.VIRIP and VIR-353 showed anti-HIV-1 activity with EC(50) of 28 and 0.3 μmol/l, respectively, and were active against virus resistant to BMS-155, AMD3100, T20, TAK-779 or nevirapine. Time of addition experiments showed that VIR-353 targets a time/site of action corresponding to gp41-dependent fusion. VIR-353-resistant virus was generated after 450 days in cell culture, suggesting a high genetic barrier for resistance. The VIR-353-resistant virus was cross-resistant to VIRIP but remained sensitive to T20, AMD3100 or zidovudine. Recombination of gp41 into a wild-type backbone partially recovered the resistant phenotype, but both gp120 and gp41 from the resistant virus were necessary to restore resistance to VIRIP or VIR-353. Site-directed mutagenesis confirmed the role of specific mutations and identified a combination of three mutations (A433T/V489I/V570I) as the most relevant to VIRIP resistance.VIRIP may interact with a region of gp41 that is essential for fusion but not the fusion peptide. Our results highlight interactions between gp41 and gp120 that may be required during the fusion process.