FIG 5.

Phenotypes of viruses with Envs containing MPER changes. Pseudoviruses containing the indicated Env variants were tested for sensitivity to cold and to antibodies/compounds directed against gp120 or gp41. Poorly neutralizing antibodies and broadly neutralizing antibodies are indicated. Cold sensitivity is reported as the half-life of infectious virus after incubation on ice. The 50% inhibitory concentrations (IC₅₀ values) of the Env ligands are reported in μg/mL except for BNM-III-170 (in μM) and BMS-806 (in nM). Some of the phenotypes were not determined (ND) due to the low infectivity of the viruses. Values are colored based on their fold increase in sensitivity (green) or resistance (red) compared to the relevant parental virus (labeled “None”). The parental and associated MPER mutant viruses were compared in parallel experiments. The results shown are means and standard deviations from two independent experiments. Additional experiments validated the relative IC₅₀ values of the parental viruses for sCD4-Ig, BNM-III-170, BMS-806, or cold. The following mean IC₅₀ values of T20 and 10E8.v4 were obtained in a side-by-side comparison of the four parental viruses (wild-type HIV-1_AD8, 2-4 RM6 AE, Q114E/Q567K and Q114E/Q567K/A582T): 0.56, 0.64, 2.5 and 0.89 μg/mL of T20, respectively; 1.7, 0.11, 2.4 and 2.0 μg/mL of 10E8.v4, respectively. Note that the increased 10E8.v4 sensitivity of the parental 2–4 RM6 AE virus relative to the wild-type HIV-1_AD8 likely results from some of the lysine changes in the 2–4 RM6 AE Env; viruses containing only the key State 1-stabilizing changes (Q114E/Q567K/A582T) do not exhibit increased 10E8.v4 sensitivity.