CD-19 specificity of bscCD19 × CD3–mediated cytotoxicity.

(A) Inhibition of bscCD19 × CD3-mediated cytotoxicity of unstimulated primary human PBLs against CD19+ target cell lines by parental anti-CD19 antibody (HD37) in a standard⁵¹Cr-release assay (E-T ratio 20:1; incubation time 4 hours; target cells Blin-1). (B) Inhibition of bscCD19 × CD3-mediated cytotoxicity of unstimulated primary human PBLs against CD19+ target cell lines by anti-CD3 antibody (OKT-3) in a standard ⁵¹Cr-release assay (E-T ratio 20:1; incubation time 4 hours; target cells Blin-1). (C)⁵¹Cr-release assay with unstimulated primary human PBLs against CD19+ Daudi cell line and CD19− plasmacytoma cell lines NCI and L363 at different concentrations of bscCD19 × CD3 (E-T ratio 20:1; incubation time 8 hours).