Fig. 4.

Neutralization susceptibility differences among X4 and R5 viruses are influenced by env V3 loop. Figures a–b show mean IC₅₀s (μg/ml) to PGT128 among co-circulating variants with different co-receptor usage in DM268 (a) and DM8 (b). Figures c–g show IC₅₀ against pooled R5 plasma (reciprocal dilution) (c–e) and PGT128 (μg/ml) (f–g) for the original R5 (white), original X4 (black), env with a R5 V3 loop in a X4 background (gray) or X4 V3 loop in a R5 background (checkers). In each graph, the subject is denoted above. Label below the x-axis denotes the env clone followed by the observed co-receptor usage in parenthesis. Star denotes significant p-value for the comparison (p < 0.05, Wilcoxon rank sum test). DM268 chimeric env MYM was not infectious (Lin et al., 2012).