HTLV-I INFECTION IN SQUIRREL-MONKEYS (SAIMIRI-SCIUREUS) USING AUTOLOGOUS, HOMOLOGOUS, OR HETEROLOGOUS HTLV-I-TRANSFORMED CELL-LINES

Peripheral blood mononuclear cells (PBMC) from three adult male squirr el monkeys (Sairnini sciureus) were transformed by human T-cell leukem ia/lymphoma virus type I (HTLV-I) by cocultivation with lethally irrad iated human MT-2 cells. Three permanent monkey T-cell lines producing HTLV-I were obtained and characterized. Six weeks after inoculation se roconversion was observed in three of three monkeys inoculated with au tologous transformed T cells and in two of three monkeys receiving hom ologous cells. Proviral DNA was detected in their PBMC at various time s after inoculation, with the highest proviral load and antibody titer s being found in monkeys infected with homologous cells. Monkeys inocu lated with heterologous MT-2 cells did not seroconvert, and HTLV-I pro virus was detected only transiently in their PBMC. To determine whethe r in vitro and in vivo HTLV-I infection of squirrel monkey cells led t o a selection of monkey-adapted viral mutants, comparative sequencing of the proviral gp21 env between ex vivo monkey HTLV-I-infected PBMC, the inoculum, and MT-2 cells was done and no significant differences w ere detected. The squirrel monkey, which is naturally free of simian T -cell leukemia/ lymphoma virus, thus appears to be a suitable model fo r evaluating HTLV-I candidate vaccines and for studying the pathogenes is of HTLV-I. (C) 1997 Academic Press.