Evaluation of a HTLV-1 subunit vaccine in prevention of experimental STLV-I infection in Macaca nemestrina.

Pig-tailed macaques were vaccinated with a human T-cell lymphotropic virus type I (HTLV-I) subunit vaccine. Vaccinates and controls were challenged with simian T-cell lymphotropic virus type I (STLV-I)-infected cells. Vaccination yielded antibody responses to HTLV-I and STLV-I gag and env precursors. Controls developed HTLV-I and STLV-I antibody to gag and tax protein. Immunization produced syncytium inhibiting antibody and cellular cytotoxicity to virus-infected cells. Reverse transcriptase activity was present in control macaques only, implying that the subunit vaccine was protective against STLV-I infection.