IMMUNE RECOGNITION OF GENETICALLY DIVERSE SIMIAN T-CELL LYMPHOTROPIC VIRUS TYPE-I ISOLATES

Nucleotide sequence analysis of selected regions of the gag, pol, env and pX genes of simian T-cell lymphotropic virus type I (STLV-I) strai ns indicated that African isolates were more closely related to human T-cell lymphotropic virus type I (HTLV-I) than Asian isolates. Despite these recent comparative studies on nucleotide sequence homology betw een HTLV-I and STLV-I isolates, only limited information is available regarding the influence of genetic differences on antigen-antibody rec ognition of distinct STLV-I strains. In this study, we demonstrated th at sera from STLV-I-infected yellow baboons (Papio cynocephalus) react ed strongly with env gp62/68 from HTLV-I-infected cell lines MT-2 and C10/MJ. In contrast, sera from Japanese macaques (Macaca fuscata) natu rally infected with Asian STLV-I had weak reactivity to env gp62/68 of these prototypic HTLV-I strains. Pst-1 restriction enzyme analysis of proviral DNA indicated that the baboon virus isolates were more close ly related to HTLV-I than the Japanese isolates. These results indicat e that nucleotide sequence diversity, correlates with variations in pr oviral restriction enzyme sites and antibody recognition of viral enve lope proteins. These differences in immunoreactivity may have importan t implications for serologic diagnosis, as well as epidemiological and vaccine studies of STLV-I infection.