HUMAN AND MURINE MONOCLONAL-ANTIBODIES DIRECTED AGAINST A CONSERVED SEQUENCE FROM GP41 (AA583-599) OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

Human spleen cells from an HIV-seropositive donor were immunized in vitro with the aa583-599 peptide conjugated to an heptalysyl core. This sequence was derived from the putatively HIV-immunosuppressive region of HIV1 gp41. The same conjugated peptide was used to immunize mice. One human and one mouse IgM monoclonal antibody (mAb) directed against the aa583-599 peptide were obtained. The two mAb had distinct patterns of reactivity against a panel of 42 peptides with modified sequences. Neither of the mAb inhibited the immunosuppressive effect of aa583-599 octopus-lys-conjugated peptide on anti-CD3 Ab-induced lymphoproliferation. In addition, both mAb did not neutralize cell-free virus transmission or enhance HIV infection. However, HmAb inhibited formation of syncytia between HIV 1 -infected (but not HIV2-infected cells) and non-infected target cells at concentrations above 20-mu-g/ml, whereas MmAb did not have any effect. The degree of conservation of the aa583-599 region makes HmAb a candidate for use as a group-specific reagent in future HIV1 passive immunotherapy protocols.