Figure 3.

Absence of Tat-directed antibody response in ISs and Ps. Antibodies to Tat in sera from uninfected controls (C), ISs, LTNPs, random HP individuals, and Ps were measured by ELISA against recombinant Tat produced in bacteria, and the OD (multiplied by 1,000 to reflect the dilution), averaged from triplicate determinations, is reported as a point for each individual. The mean for each group is indicated by a bar, with SEM flags. (Lower) Mean antibody titer of each group to Tat and HIV proteins (Abbott Diagnostic Labs, Chicago, to gp41 envelope and p24 nucleocapsid) determined by linear regression analysis of ELISA readings at 1:10,000, 1:1,000, and 1:100 dilutions for Tat, and at 1:1,600 and 1:400 dilutions for HIV. The anti-HIV titers are a lower estimate as some samples exceeded the maximum range of this assay (>20,000). The difference in anti-Tat antibody response between the LTNP and either the IS or the P groups is highly statistically significant (P < 0.0003 vs. IS, P < 0.0024 vs. P, unpaired t test), whereas the difference in antibody between the LTNP and the HP groups is also statistically significant (P < 0.02, unpaired t test).