The effects of tumor promoters on HTLV-1 expression in a low-virus producer and a non-virus producer cell line.
Chemical agents including 5-iodo-2'-deoxyuridine (IUdR), 4-O-methyl 12-O-tetradecanoyl phorbol-13-acetate (TPA), phorbol, and the tumor promoters teleocidin and TPA were tested for their ability to induce Human T-cell leukemia-lymphoma virus Type I (HTLV-I) expression in the low-virus producer MT-1 cell line and in the non-virus producer C63/CRII-2 cell line, which contains at least one integrated HTLV-I genome equivalent per cell [26]. Viral antigen expression increased from 0.3% to 8.7% in the MT-1 cell line after treatment with IUdR, while TPA and teleocidin were marginally or non-effective as inducers. Chemicals did not induce HTLV-I antigen expression in the C63/CI(II-2) cell line. No enhancement of reverse transcriptase activity or alteration of proviral organization was observed after chemical treatment of MT-1 cells.