CD28 and familial pancreatic carcinoma: To address whether the MSLN expression on the pancreatic cancer cells activates MSLN-targeting CAR T cells, we generated MSLN-CAR T cells by transducing murine splenic T cells with a retrovirus harboring second-generation CARs, which included an MSLN-targeting scFv, CD3ζ, CD28 co-stimulatory signaling molecules, and GFP (Fig. S5a).