Cytotoxic T cells (Tc) derived from one patient with
adult T cell leukemia/lymphoma (ATL) killed fresh autologous
lymphoma cells in vitro. The Tc were induced from peripheral blood leukocytes (PBL) of this patient during remission by multiple in vitro stimulations with an autologous ATLV-bearing cell line (ILT) that was previously established by cloning of PBL in the presence of
interleukin 2 (IL 2). PBL from eight other ATL patients were stimulated in the same manner, and responder cells from a patient in remission also showed cytotoxicity specific for ATL virus (ATLV)-bearing cells. Fresh
lymphoma cells were obtained in relapse and were used as target cells for the autologous Tc induced. They became susceptible to the Tc within 4 hr of in vitro incubation, and their susceptibility increased with incubation time for at least 12 hr.
ATLV antigens on the cell surface of these
lymphoma cells, however, were not detected by radioimmunoassay during these incubation periods, but were detectable after 16 hr of incubation. In addition, cytotoxicity against
lymphoma cells was completely inhibited by autologous ILT cells used as "cold" target competitor cells. These findings indicate that the target
antigen of the Tc was expressed on both autologous ILT cells and
lymphoma cells, and it may be different from
ATLV antigens detected by serologic methods. In addition, the data suggested allogeneic restriction of the Tc in that the preferentially killed allogeneic ATLV-bearing cells share several
HLA antigens.