CD40 and colitis: MCP-1 was not upregulated in the CD40KO DSS + MC-LR group and there is a significantly lower MCP-1 level in the CD40KO DSS + MC-LR group as compared with WT DSS + MC-LR group, demonstrating that knocking out CD40 prevents the subsequent production of the pro-inflammatory cytokine MCP-1 even in the setting of MC-LR exposure in pre-existing colitis (Figure 7A).