Demonstration of the specific lysis of cancer cells coated with different Fab-HLA-A2/Flu peptide conjugates, by a relevant CTL clone at different effector to target cell ratios. (A) Specific lysis, in a ⁵¹Cr release assay, of LoVo colon carcinoma target cells preincubated with anti-CEA Fab-HLA-A2/Flu (filled squares) and no lysis of the CEA negative SK-BR-3 cells (open circles) preincubated with the same conjugate. (B) Specific lysis of SK-BR-3 induced by anti-ErbB-2 Fab-HLA-A2/Flu (filled circles) with minimal lysis of LoVo cells (open squares) or Daudi cells (open diamonds) preincubated with the same conjugate. (C) Specific lysis of Daudi (filled diamonds) and Raji (crosses) cells preincubated with anti-CD20 Fab-HLA-A2/Flu with no lysis of LoVo (open squares) or SK-BR-3 (open circles) cells preincubated with the same conjugate. In all panels, the conjugate concentration was 2 µg/ml. Results are expressed as % specific target cell lysis.