CHARACTERIZATION OF AN IL-2 DEPENDENT HUMAN T-CELL LEUKEMIA-VIRUS TYPE-I (HTLV-I) INFECTED CELL-LINE - A SYSTEM FOR STUDYING HTLV-I MEDIATED TRANSFORMATION

The retrovirus Human T cell Leukemia Virus type I (HTLV-I) is the caus ative agent of Adult T cell Leukemia Lymphoma (ATLL) and is associated with HTLV-I Myelopathy. HTLV-I mediated transformation of CD4(+) T ce lls, during the course of ATLL, is poorly understood. It has been sugg ested that HTLV-I is responsible for the immortalization of infected c ells, but transformation is dependent on secondary events. To investig ate this hypothesis, we have isolated an HTLV-I infected T cell line t hat is dependent on IL-2 for growth in tissue culture. Further, a subc lone of this cell line that is able to grow in the absence of IL-2 has been isolated. Both cell lines have identical TCR chain rearrangement s and cell surface markers. Each,cell line produces viral mRNAs and pr oteins. Finally, both of these cell lines are sensitive to rapamycin a nd cyclosporin A regardless of the presence of IL-2. We propose that t his system will provide a unique opportunity to study transformation t o IL-2 independence in HTLV-I infected cells.