AFAP1 and neoplasm: When combinations of αEpCAM and αFAP BiMAb were cultured with T cells in the absence of MCF-7 cells, no activation or proliferation was observed (Figures 1D, F and Supplementary Figures 1A, C), further supporting the conjecture that T cell-activating effects of tetravalent bispecific antibodies analyzed here were strictly dependent on T cell–tumor cell cross-linking.