CD4 and colitis: The low IFN-γ levels produced by animals subjected to TNBS administration could be due to the period of time spent by LP CD4+ T cells to express the transcription factor T-box expressed in T cells (T-bet), which appears to be critical to the initiation and perpetuation of colitis mediated by Th1 cells [45] and whose action appears to precede the IL-12/STAT4 pathway.