Fig. 1.
BsAb-mediated cytotoxicity in vitro.
Tumor cell killing was measured by a colorimetric MTT-based assay. (A) Varying E/T ratios were carried out with a constant amount of 50 ng/mL bsAb BiLu (▪) or bsF(ab′)2 (▵) targeted against transfected B16-EpCAM cells. To differentiate antigen-independent cell lysis by the bsAb, nontransfected B16 target cells were used (bsAb wild-type, ■). (B) At an E/T ratio of 20:1, the bsAb BiLu (▪) and bsF(ab′)2 (▵) were titrated from 50 to 0.05 ng/mL. Controls with the parental antibodies were performed at equimolar amounts (17A2+C215, *; and C215, ○). B16-EpCAM cells were used as targets. Effector cell-induced background lysis in the absence of antibody was subtracted.
