Extended Data Fig. 2: Cytolysis of BT20 and MDA-MB-468 breast tumor cell lines by T cells incubated with the HER2 trispecific Ab and mutants and correlation in target cell lysis with HER2 density on tumor cell lines.
From: A trispecific antibody targeting HER2 and T cells inhibits breast cancer growth via CD4 cells
a, Cytolysis of HER2-expressing breast cell line BT20, and HER2-negative breast cell line MDA-MB-468, were assessed with HER2 trispecific Ab in vitro using CD8+ as effector cells (E:T = 3:1). The crucial contribution of anti-HER2 arm of the trispecific Ab is demonstrated with the single binding site inactivating mutant. b, Correlation in target cell lysis with HER2 density on tumor cell lines. Additional breast tumor cell lines, along with gastric tumor cells lines, (HCC1954, MDAMB453, HCC1143, MDAMB231, OE.19, GSU, and MKN-45) were measured for HER2 surface protein expression using QIFI kit (Dako, Denmark) as described in Methods. Cytolysis of the tumor targets with HER2 trispecific Ab was assessed in vitro using CD8+ effector cells. The EC50 for target cytolysis was calculated for each tumor cell line (left) and the maximum percentage of dead target cells was also calculated for each tumor cell line (right).
