CTL Clone CTL-7A7 recognizes a HLA-A^*0301-restricted mHAg that is selectively expressed in B-lymphoid cells. (A) The cytolytic activity of CTL-7A7 CTLs against EBV-LCLs, PHA-stimulated T-cell blasts, unfractionated peripheral blood mononuclear cells (PBMCs), and dermal fibroblasts derived from the transplant recipient (Recip) or donor was evaluated in a 4-hour ⁵¹Cr release assay at the indicated effector-target ratios. (B) Cytolytic activity at E/T 10:1 of CTL-7A7 CTLs against a panel of EBV-LCLs derived from unrelated individuals, each of whom shared 1 class I MHC allele with the recipient-donor pair from whom the CTL clone CTL-7A7 was derived. The specific class I MHC allele shared with the recipient/donor by each individual is indicated.