CROSS-REACTIVE POTENTIAL OF RABBIT ANTIBODIES RAISED AGAINST A CYCLICPEPTIDE REPRESENTING A CHIMERIC V3 LOOP OF HIV-1 GP120 STUDIED BY BIOSENSOR TECHNIQUE AND ELISA

Rabbit antibodies were induced against a free cyclic peptide represent ing the chimeric sequence of a consensus V3 loop of HIV-1 gp120. The r eactivity of these antibodies was tested in a biosensor system (BIAcor e (TM), Pharmacia AB, Uppsala, Sweden) and in ELISA with the peptide i mmunogen in its cyclic and linear forms, as well as with peptides corr esponding to the V3 region of different HIV-1 variants. The antibodies reacted with all the peptides tested both in ELISA and in biosensor a ssays and recognized the cyclic form of the chimeric peptide better th an the linear form. Although antibodies raised against the V3 region o f particular HIV-1 variants cross-react with other HIV-1 strains, it s eems that the use of a chimeric peptide as immunogen improved the cros s-reactivity spectrum of recognition of the antibodies. The anti-V3 an tibodies were also tested for their ability to neutralize in vitro fou r HIV-1 laboratory strains. Only the HIVMN variant was found to be neu tralized. Compared to conventional solid phase immunoassays, the BIAco re presents several advantages for measuring the differential reactivi ty of peptide analogues. In view of their broadly cross-reactive poten tial, antibodies raised against a consensus sequence should be useful in immunodiagnosis of viral antigenic variants.