Figure 2

HIV-1 neutralization of various isolates by different sCD4-17b constructs and related proteins. Assays were performed using the TZM-bl system or where indicated, with the MAGI-CCR5 system. Dose-response analyses were performed with the indicated proteins and HIV-1 Env pseudotypes or infectious virus, as indicated by the symbols above the graphs and the names within the graphs. Each point represents the mean of duplicate samples; error bars indicate SD. A) Comparison of the potencies of sCD4-35-17b and sCD4-40-17b against the 91US054 pseudotype and infectious virus. In the TZM-bl system, the IC₅₀ values against the pseudotype were 11 nM for both sCD4-35-17b and sCD4-40-17b; the value against the infectious virus was 22 nM for sCD4-40-17b. In the MAGI-CCR5 system, the IC₅₀ value against the infectious virus was 30 nM. B) Comparison of the effects against the indicated Env pseudotypes of sCD4-40-17b, sCD4-5-17b (shorter linker) and proteins representing individual moieties (sCD4 alone, or in combination with 17b SCFv). The IC₅₀ values for sCD4-40-17b were 12.3 nM against CAAN5342.A2, 9.8 nM against RW020, and 0.8 nM against YU2; the value for sCD4-5-17b against YU2 was 16.5 nM.