Specific inhibition of the Fab-HLA-A2/Flu induction of CTL mediated tumor cell lysis by a competing antibody. To further demonstrate the antibody specificity of the induction of cancer cell lysis by Fab-HLA-A2/Flu conjugates, intact anti-ErbB-2 mAb (Herceptin) was added at 20 µg/ml (open symbols) or not added (filled symbols) with increasing concentrations of anti-ErbB2 Fab-HLA-A2/Flu on SK-BR-3 cells (A) or LoVo cells (B). Results are expressed as % specific target cell lysis.