FIG. 2.

Temporal antibody responses. (A) Temporal assays of anti-Env binding, anti-Env neutralizing, and anti-Gag binding antibodies. Micrograms of total antibody against SIV239 Gag or 89.6 Env were determined using ELISAs. The titers of neutralizing antibody for SHIV-89.6 and SHIV-89.6P were determined using MT-2 cell killing and neutral red staining (16). Neutralization titers are the reciprocal of the serum dilution giving 50% neutralization of the indicated viruses grown in human PBMC. Symbols for animals are the same as those in Fig. 3. Data for the Gag-Pol-Env groups are in part reproduced from reference 2. (B) Avidity of anti-Env binding antibody at 2 weeks postchallenge. GM, geometric mean titer.