ERBB2 and neoplasm: Furthermore, T cells engineered with a chimeric antigen receptor (CAR) containing a single chain variable fragment (scFv) based on the monoclonal Ab (mAb) clone 4D5 that recognizes human epidermal growth factor receptor 2 (EGFR2/HER2) antigen and the endodomains of CD96 and CD3ζ (4D5-96z CAR-T cells) killed HER2-expressing tumor cells less efficiently in vitro and in vivo than T cells engineered with a CAR containing the same scFv and the endodomain of CD3ζ alone (4D5-z CAR-T cells).