 Moreover, there are two antigenic epitopes (CypB84-92 and CypB91-99) recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes which could be used as cancer vaccines, and in fact, were used to treat lung cancer in a clinical trial.PPIB has been identified in both Gram-negative bacteria and Gram-positive bacteria as an intracellular protein.In "Escherichia coli", PPIB has been shown to have both PPIase activity and Chaperone (protein) activity.