Expression of CR2 (C3d receptor) on the cell membranes of adult T cell leukemia.

MT-2 cells, which produce human T-cell lymphotropic virus type I (HTLV-I), are known to have a complement receptor. We have established that the complement receptor is CR2 which binds C3d on immune complexes but not CR1. CR2 was also detected on ATL-3I cells but no complement receptor was detected on ATL-1K cells which lack ATL antigen (ATLA). Since CR2 is not detectable on normal T lymphocytes, the presence of CR2 on some ATL cells might suggest that ATL cells were derived from a particular minor lineage of T cells, or HTLV-I has a capacity to induce CR2, which has been demonstrated to be an a-type growth factor for B lymphocytes and to be a receptor for Epstein-Barr virus.