Definition

A bispecific antibody directed against both the tumor-associated antigen (TAA) prostate-specific membrane antigen (PSMA) and the co-stimulatory T-cell-specific surface glycoprotein CD28, with potential immunostimulating and antineoplastic activities. Upon administration, anti-PSMA/anti-CD28 bispecific antibody JNJ-87189401 binds to both CD28 expressed on cytotoxic T lymphocytes (CTLs) and PSMA expressed on tumor cells. This activates and redirects CTLs to PSMA-expressing tumor cells, which may result in the CTL-mediated cell death of PSMA-expressing tumor cells. PSMA is overexpressed on the surface of metastatic and hormone-refractory prostate cancer cells.