CIITA and ovarian cancer: Two DP4+ ovarian cancer cell lines (OV2774 and OVCAR-5) were transduced with a self-inactivating bicistronic retroviral vector encoding class II transactivator (CIITA), which induced cell surface MHC-II expression, and NY-ESO-1 or control human sperm protein 17 (Sp17) gene (Supplementary Fig. S1A).