Specific induction of intracellular Ca²⁺ mobilization in cytotoxic T lymphocytes incubated with SK-BR-3 breast carcinoma cells coated with anti-ErbB-2 Fab-HLA-A2/Flu conjugates. Ca²⁺ mobilization was analyzed by cytofluorometry on the same influenza matrix peptide-specific T cell clone preincubated for 2 min at 37°C with (A) uncoated SK-BR-3 cells, (B) soluble conjugate at 5 µg/ml, (C) SK-BR-3 cells precoated by incubation with anti-ErbB2 Fab-HLA-A2/Flu conjugate at 5 µg/ml, (D) anti-CD3 mAb at 5 µg/ml crosslinked with goat anti-mouse antiserum. Left panels show the dot plot results for the 250 s recorded time. Right histogram panels show the percent of positive cells during the whole recorded time.