A COMMON IMMUNOLOGICAL EPITOPE EXISTING BETWEEN HIV-1 GP41 AND HUMAN INTERFERON-ALPHA AND INTERFERON-BETA

Based on the similar effects that HIV-1 gp41 like human type I interfe rons (IFN-alpha and -beta) upregulated MHC expression and inhibited ly mphocyte proliferation, we compared amino acid sequences of gp41 and h uman type I interferons (IFN-alpha and -beta), and found sequence-simi larity existing between the immunosuppressive domain (aa583-599, LQARI LAV-ERYLKDQQL) of HIV-1 gp41 and human IFN-alpha (region aa117-129) an d IFN-beta (region aa128-134); besides, the immunosuppressive domain o f HIV-1 gp41 shows sequence-homology with bovine and murine IFN-alpha and IFN-beta in the same region. We examined polyclonal antibodies to human IFN-alpha and IFN-beta respectively and found that both antibodi es could recognize rsgp41 from two different sources. The polyclonal a ntibody to IFN-beta could bind to the immunosuppressive peptide (ISP, aa583-599, LQARILAVERYLKDQQL) of HIV-1 gp41, only when the ISP was cou pled with carrier-protein, and inhibit, if preincubated with rsgp41, b inding of rsgp41 to human H9 (T cells), Rail (B cells), and U937 (mono cyte cells) completely. The polyclonal antibody to IFN-alpha could par tially inhibit the binding of rsgp41 to U937 and Raji. These results i ndicate that a common immunological epitope exists between HIV-1 gp41 and human type I interferons.