ANTIBODY TO HISTO-BLOOD GROUP-A ANTIGEN NEUTRALIZES HIV PRODUCED BY LYMPHOCYTES FROM BLOOD GROUP-A DONORS BUT NOT FROM BLOOD GROUP-B OR GROUP-O DONORS

Three virus isolates HTLV-III(B)/lyA, HTLV-III(B)/lyB and HTLV-III(B)/lyO, obtained by passaging and propagating the HTLV-III(B)/H9 isolate in three separate cultures of mixed peripheral blood mononuclear cells (PBMC) from donors of blood type A, B or O, respectively, were tested for susceptibility for virus neutralization by the monoclonal antibody (MAb) AH16 directed against the blood group A epitope. MAb AH16 was previously shown to inhibit cell-free virus infection using HTLV-III(B) propagated in H9 cells. AH16 showed a concentration-dependent inhibition of the HTLV-III(B)/lyA isolate but did not inhibit the HTLV-III(B)/lyB or the HTLV-III(B)/lyO isolate. Specificity of the MAb-mediated inhibition was shown using A-antigen (tetrasaccharide). Thus, HIV infection of PBMC from donors with blood type A appears to induce expression of host-cell-encoded carbohydrate blood group A epitope on HIV which can be a target for MAb-mediated virus neutralization.