FIG. 2.

Breadth and potency of HIV-1-specific neutralizing activity in sera obtained during the course of infection from three LTNP (top) and three progressors (bottom). IC₅₀s, given as the reciprocal serum dilution determined using a U87-based neutralizing assay, are shown for serum samples obtained during the course of infection against a panel of 23 heterologous virus variants. Due to limiting amounts of serum, some sera were only tested against a subset of this virus panel. In the left columns, a description of the virus panel is given; the tier 2-3 virus panel consisted of HIV-1 pseudoviruses from subtype A, B, C, and D. The references panel (bottom part) included strains 1196, BaL, JRCSF, NL4-3, and SF162. As a negative control (NC), the amphotropic murine leukemia virus was used. IC₅₀ titers ≥ 1:100 and exceeding three times the background reading for that sample are indicated in gray. n.d., not done.