CD28 and osteosarcoma: Though cytokine release varied between PBL donors, cytokine release from the TP41.2-CD28.CD3ζ construct was consistently high in all three donors.PBL from two additional donors were transduced with the three reactive CARs and cocultured with CSPG4-positive cell lines from multiple different histologies including the glioblastoma cell line A1207, the breast cancer cell line MDAMB231, the mesothelioma cell line Mill, the osteosarcoma cell line MgG-63 and the melanoma line mel938.