ISOLATION AND CHARACTERIZATION OF SIMIAN T-CELL LEUKEMIA-VIRUS TYPE-II FROM NEW-WORLD MONKEYS

Since the description of human T-cell leukemia virus type I (HTLV-I) a nd its simian counterpart, simian T-cell leukemia virus type I (STLV-I ), the possible existence of other related simian retroviruses has bee n raised. Here, we report a new retrovirus, STLV-II, which we have ide ntified in spider monkeys (Ateles fusciceps), a New World primate spec ies. Initially, a recombinant HTLV-II envelope protein (RP-IIB) was us ed to identify anti-STLV-II antibodies in New World monkeys by Western blot (immunoblot) assays. Subsequently, the virus was characterized b y Southern blot hybridization, which showed that STLV-II and HTLV-II h ave a high degree of nucleotide sequence homology but have different r estriction enzyme patterns. Nucleotide sequence analysis of the pX-II region of STLV-II provirus revealed 3% variation with the correspondin g region of HTLV-II. Electron micrographic studies revealed HTLV-like, type C retrovirus particles outside the cell membranes of STLV-II-inf ected cells. This study describes the first link between HTLV-II and a simian reservoir in the New World. Further molecular studies of STLV- II infection in different species of New World monkeys, especially fro m the wild, may provide valuable information about the origin and intr agroup relationships of South American monkeys. Spider monkeys infecte d with STLV-II may serve as an important animal model for HTLV-II infe ction in humans.