FIG. 4.
(A) Infections mediated by CCR5(G163R)-expressing clonal cell lines. The curves with open symbols show the levels of HIV-1 infections of HeLa-CD4-CCR5(G163R) cells as determined by a focal-infectivity assay which uses p24gag immunoperoxidase staining to detect foci. The filled symbols indicate infections of HeLa-CD4-CCR5 cells expressing wild-type (wt) CCR5 (clones JC.10 and JC.53, with ca. 6 × 103 and 2 × 105 CCR5 molecules/cell, respectively). The isolates used were JRCSF (diamonds) and BaL (squares). The titer on each cell clone was determined by dilution of virus stocks and multiplying the number of foci observed by the dilution factor as described in Materials and Methods. The relative infectivity was determined by dividing the titer determined on a given cell clone by the titer determined on HeLa-CD4-CCR5 (clone JC.53) cells with the same virus stocks in the same assay. Thus, the relative infectivity of the JC.53 cell clone shown in this graph was 1 by definition. Each point is the average of results of five to seven experiments, and the error bars represent the SEM. (B) Infections mediated by CCR5(Y14N)-expressing cell lines. The isolates used were JRCSF (diamonds) and BaL (squares). The titers were normalized as described for panel A. Each point is the average of results of three to eight experiments, and the error bars represent SEM.