Cross-reactivity of anti-HIV-1-p17-derivative peptide (P30-52) antibody to Env V3 peptide.
Strong antibody responses are often seen in human immunodeficiency virus type 1 (HIV-1) carriers, but it is not known whether these antibodies are effective in the inhibition of disease progression. In this study, we examined antigenic epitopes for anti-HIV-1 p17 antibody (p17 Ab) in an HIV-1 carrier's serum, and found that the residues of amino acid numbers 1 to 12 (P1-12), 12 to 29 (P12-29) and 30 to 52 (P30-52) of p17 were highly recognized in the serum. Our examination of purified antibodies from the patient using the p17-derivative-peptide-immunoaffinity columns showed that the reactivity of anti-p30-52 Ab (p30-52Ab) was high for p30-52 and the naive protein, p17. In addition, this P30-52Ab cross-reacted with the third variable region of the envelope glycoprotein (Env V3). To confirm this cross-reactivity, we immunized mice with P30-52, and established a monoclonal antibody (MAb), 8H10. We found that 8H10 was also reactive to Env V3. It is unclear whether this cross-reactivity of P30-52 Ab can function as the inhibitor of HIV-1, but these results will be of help in clarifying the interaction of Env protein with HIV-1 gag polyprotein and the relationship of the decline of the p17 antibody titer with the disease progression in HIV-1 carriers.