(A) Surface ICAM-1 and CD19 expression of 12 different CD19⁺ B-cell lines (expressed as MFI) correlated with their sensitivity to anti-CD19-Fab-SEAm plus T cells. A logarithmic curve fit is shown for the ICAM-1/cytotoxicity correlation. (B) Effect of TNFα treatment of 2 pre-B-cell lines. Cell surface CD19 and ICAM-1 expression and sensitivity to anti-CD19-Fab-SEAm–mediated T-cell lysis (fusion protein concentration 0.5 ng/mL) is shown. The pre-B-cell lines (NALL-1 and NALM-1) were stimulated with TNFα (1,000 U/mL for 40 hours). Surface antigen expression and sensitivity of nonstimulated cells is presented as 1.0 (horizontal bar) to allow comparison to stimulated cells. Each value is the mean of triplicate samples. ▧, CD19 expression; , ICAM-1 expression; ▪, sensitivity to lysis.