FIG. 5.

Neutralization sensitivity of R5, R5X4, and X4 SHIVs. The neutralization susceptibility of the parental R5 SHIV_SF162P3N (•), the final X4 SHIV_BR24N (▵), and the R5X4 intermediate (□) virus to antibodies in serum from R5 SHIV_SF162P3N-infected (R5-SHIV serum) and X4 SHIV_BR24N-infected (X4-SHIV serum) macaques (A) and to soluble CD4 (CD4-IgG2) and MAbs IgG1b12, 447-52D, 2G12, 2F5, and 4E10 (B) was determined in TZM-bl cells as described in Materials and Methods. Data shown are the means and standard errors of at least three independent neutralization experiments.