Poly-functional T helper cells in human tonsillar mononuclear cells.

Tonsils are important lymphoid organs in which B cells and T cells complete their maturation and identify cells that are infected by pathogens. However, the functions of T cells in human tonsils remain unclear, especially the characteristics of polyfunctional CD4⁺ T helper cells. In this study, we used multi-color flow cytometry to analyze the expression or co-expression of effector cytokines in CD4⁺ T cells from tonsillar tissues. We have demonstrated that tonsillar CD4⁺ T cell can express various Th effector cytokines after short-term polyclonal stimulation, and that cytokine-producing CD4⁺ T cells were CD45RO⁺ T cells. In addition, we analyzed the co-expression of two or more kinds of cytokines at the level of a single cell. The results showed that tonsillar CD4⁺ T cells exhibited polyfunctionality by co-expressing two to five kinds of cytokines in the same time. These data furnished a basic theory for further understanding the differentiation of polyfunctional Th cells in human tonsils and their functions in resisting invasive microorganisms.