Monoclonal antibodies were developed to a recombinant HIV-1 group O envelop
e protein derived from the isolate HAM112. These monoclonal antibodies were
characterized for reactivity to a series of overlapping synthetic peptides
(29-30 mers) covering gp120 C-terminal and gp41 ectodomain regions of the
HIV-1 group O envelope protein. Most of these monoclonal antibodies reacted
with peptides spanning sequences analogous to HIV-1 group M epitopes ident
ified from studies in mice and humans. However, several of the antibodies t
hat were nonreactive to individual peptides did react to a mixture of longe
r peptides from the N-terminal and C-terminal helical regions of the gp41 e
ctodomain. The monoclonal antibodies described in this study are valuable t
ools for characterization of antigenic differences between HIV-1 group O an
d group M viruses.