FUNCTIONAL COMPARISON BETWEEN HTLV-I ENVELOPES ORIGINATING FROM TSP HAM OR ATL CELL-LINES/

The human T-cell leukemia type I (HTLV-I) virus is associated with two different diseases, adult T-cell leukemia (ATL) and tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We have compared t he viral envelopes originating from TSP/HAM and ATL patients, using th e capacity of infected cells to form syncytia with receptor-expressing cells. We show that like the ATL cell lines, the TSP/HAM ones can for m syncytia with a large panel of human target cells, including a varie ty of hematopoietic cell lines, as well as cell lines of neuroectoderm al origin. None of the target cell lines tested was able to discrimina te between TSP/HAM- and ATL-infected cell lines. When infected cells o f TSP/HAM origin are cocultivated with cells of ATL origins, syncytia are never observed. This interference phenomenon suggests that the vir uses expressed by the different cell lines utilize the same receptor.