CIRCULATING ANTI-TAX CYTOTOXIC T-LYMPHOCYTES FROM HUMAN T-CELL LEUKEMIA-VIRUS TYPE I-INFECTED PEOPLE, WITH AND WITHOUT TROPICAL SPASTIC PARAPARESIS, RECOGNIZE MULTIPLE EPITOPES SIMULTANEOUSLY

CD8(+) T cells were freshly isolated from a human T-cell leukemia viru s type I (HTLV-I)-infected patient with tropical spastic paraparesis. These cells, which were specific for HTLV-I Tax, simultaneously recogn ized a minimum of five, and possibly as many as seven, distinct peptid e epitopes within the protein. A further Tax epitope was recognized af ter a short period of culture without exogenous peptide stimulation. A ll but one of these epitopes were clustered in the N-terminal third of Tax, and one of the epitopes was clearly immunodominant on two separa te occasions of testing. Recognition of the immunodominant epitope was restricted by human leukocyte antigen (HLA) B15, and recognition of a ll the others was by HLA A2. Similar patterns of cytotoxic T lymphocyt e recognition of the HLA A2-restricted Tax peptides in two healthy HTL V-I-seropositive individuals, each of whom carried the HLA A2 allele, were observed.