The in vitro antitumor response of TC-210 and TC-210 + PD1-CD28 CSRs was assessed using the mesothelioma cell line, MSTO-211H, engineered to express human MSLN (MSTOMSLN) or MSLN and PD-L1 (MSTOMSLN-PD-L1). Here, CD28 is linked to mesothelioma.