Fine specificity of human HLA-B7-specific cytotoxic T-lymphocyte clones. I. Identification of HLA-B7 subtypes and histotopes of the HLA-B7 cross-reacting group.

Three HLA-B7-specific cytotoxic T lymphocyte (CTL) clones are described. Their fine specificity is examined by extensive panel and family studies. Four CTL-defined subtypes of HLA-B7 could be found: HLA-B7.1, -B7.2, -B7.3, and -B7.4. Biochemical evidence was obtained in one-dimension isoelectric focusing for only two subtypes. The estimated subtype frequencies in the Caucasian population are presented. Furthermore, a linkage disequilibrium between HLA-A29 and HLA-B7.3 is suggested. The CTL clones exerted distinct "extra-reactivities", i.e., lysis of some non-B7 target cells. These extra reactivities could be assigned to the cross-reacting group of HLA-B7.