Mechanisms underlying the induction of IL-2 secretion by PDB plus ionomycin in CD4~+CD25~+ T cells from cord blood and adult peripheral blood / 中国病理生理杂志

ABSTRACT

AIM: To confirm that CD4~+CD25~+ regulatory T cells don't have an instinctive defection in IL-2 secretion, and to have an insight into the maturation state of CD4~+CD25~+ T cells in cord blood. METHODS: CD4~+CD25~+ and CD4~+CD25~- T cells were purified from cord blood of term infants (CB) and adult peripheral blood (PB) by autoMACS, and stimulated with PDB plus ionomycin. After 45 hours of culture, cells were detected for expression of CD69 and CD25 by flow cytometry, and the supernatants were measured for 7 kinds of cytokines by Luminex. RESULTS: CD4~+CD25~+ T cells from both CB and PB proliferated comparably with CD4~+CD25~- T cells when stimulated with PDB plus ionomycin. After 45 hours of culture, however, the CD4~+CD25~+ T cells underwent a tendency of cell death. Expression of CD25 was further upregulated when CD25~+ cells were activated. Under stimulation of PDB plus ionomycin, both CD4~+CD25~+ and CD4~+CD25~- T cells in PB secreted high levels of IFN-?, IL-2 and TNF-?, with CD25~+ cells secreted much higher level of IL-5, IL-4 and IL-10 than those in CD25~- cells; CD4~+CD25~+ and CD4~+CD25~- T cells in CB also secreted high level of IL-2 and TNF-? but much lower level of IFN-? than those in PB, and no secretion of IL-5, IL-4 and IL-10 was observed. CONCLUSION: CD4~+CD25~+ regulatory T cells don't have an instinctive defection in IL-2 secretion, otherwise there may be a different TCR signaling pattern in CD4~+CD25~+ T cells from traditional T cells. The CD4~+CD25~+ T cells in cord blood have not fully matured in function.