CD4 and colitis: The total of special memory T cells (as CD45RA+CD62L+CCR7+ and CD4+CCR7+CD62L+T cells) and memory T follicular helper cell (mTfh; as CD4+CCR7+CXCR5+T cells) were markedly decreased, while the expressions of CD4+, CD8+, GL7+, CD62L+ molecules on the surface of memory T cells and mTfh cells were distinctly reduced in the DSS mice, which suggested that low-level immune memory has an important role in DSS-induced colitis in the present study.