Autologous B-LCL transfected with full-length BCR-ABL^b2a2 cDNA are lysed by b2a2 fusion peptide-specific clones Aa3 (solid bars) and Aa14 (hatched bars) only after cotransfection with Ii^b2a2 (invariant chain construct in which part of CLIP was replaced by a b2a2 joining region sequence) and/or incubation with b2a2 peptide.