CTLA4 and colitis: To demonstrate the functional role of CD80 in immune surveillance during carcinogenesis progression, at the end of the AOM-DSS colitis protocol we administered neutralizing antibodies against either CD80 or CTLA4 to inhibit or enhance CD80 signaling, respectively [19] and against CD8 to assess the role of cytotoxic T cells in this process (Figure 6A–6B).