CTLA4 and ovarian neoplasm: Our previous study demonstrated that combined anti-CTLA4/PD-1/CD137 mAbs induce a potent antigen-specific Th1 type immune response in spleens from ID8-bearing mice [27], whose splenocytes produced high levels of IFN-γ upon stimulation by peptide derived from ID8 cell-expressing mesothelin, a well-characterized ovarian tumor antigen [9].