Abstract: Peptides corresponding to epitopes of HTLV-2 proteins are provided. These peptides are immunologically reactive with HTLV-2 specific antibodies. Several of the peptides are sufficiently unreactive to antibodies to HTLV-1 to distinguish between antibodies which recognize HTLV-1 and those which recognize HTLV-2. Thus HTLV-1 infections can be distinguished from HTLV-2 infections. The peptides are useful in assays for detection of HTLV-2 infection or exposure. The peptides are also useful as vaccine compositions against HTLV-2. Antibodies generated in response to immunization by the peptides are also provided.