Figure 4

V1V2 deletion impacts on trimer stability. (A) Susceptibility of wt (black) and ΔV1V2 envs (red) to CD4-induced shedding was probed on env-transfected 293-T cells by flow cytometry. Percent of gp120 shedding upon incubation of env-expressing cells with CD4-IgG2 in relation to mock-treated controls is shown. Bars depict mean and SD of 2 independent experiments. (B) The half-life of wt and ΔV1V2 env virus stocks was determined by incubation for up to 80 h with periodic sampling and infectivity assessment on TZM-bl cells. Data points are means from 2 to 3 independent experiments. (C) Wt and ΔV1V2 virus stocks were subjected for 5 h to temperature gradient from 25°C to 45°C in 2.5°C steps followed by infectivity assessment on TZM-bl cells. The temperatures at which 50% infectivity of each stock remained are depicted. Data points are means of 2 to 3 independent experiments performed in duplicates.