FIG. 4.

Replicative fitness of V3 polymorphisms in three envelope contexts. Each chimeric virus was competed in pairwise dual infection in PHA/IL-2-activated PBMC against a panel of CCR5-tropic primary isolate viruses (B2-92BR017, Yu-2, B5-91US056, C5-97ZA003, A1-92RW009, and B10-92BR003). Relative fitness values were calculated as described in Materials and Methods. Plots are of fitness difference values and are indicative of fold difference replication capacity. Fitness differences are plotted on a logarithmic scale, and bars that fall above the midline (W_D = 1) indicate competitions in which the chimeric virus was the winner, whereas bars falling below the midline indicate competitions in which the primary reference isolate was the winner. Bars that lie near the midline (W_D = 1) indicate competitions in which both viruses were of nearly equivalent replicative fitness. All competitions were performed in duplicate. (A) Fitness order of full-length viruses used in the reference panel. (B) Fitness difference values of NL4-3-V3_A1-92RW009 chimeric viruses with V3 polymorphisms against the reference panel. (C) Fitness difference values of NL4-3-gp120_B5-91US056 chimeric viruses with V3 polymorphisms against the reference panel. (D) Fitness difference values of NL4-3-gp160_Yu-2 chimeric viruses with V3 polymorphisms against the reference panel.