Abstract: Objective To investigate the effect of IL-2 on the differentiation of mice spleen CD4+CD62L+T cells into Th17 in vitro. Methods CD4+CD62L+T cells from C57BL/6 mice with MACS were divided into two groups, control group and IL-2 treated group, to be cultured in anti-CD3 and anti-CD28 antibody coated plate for 3 days. Control group cells were cultured in classical Th17 conditional medium, while IL-2 was added into the conditional medium of IL-2 treated group. Cell proliferation, cell apoptosis, the concentration of cytokine IL-17A, expression level of specific transcription fator Rorγt, and percentage of CD4+IL-17+Th17 were measured by CFSE fluorescent staining, Annexin V-PI, ELISA, qRT-PCR, and FACS, respectively. Results The purity of separated CD4+CD62L+na?veT was more than 95%. Compared with control group, the proliferation was improved (P<0.05) with a reducing apoptosis (P<0.05) in IL-2 treated cells. Moreover, IL-2 treated cells produced significantly lower concentration of IL-17A (P<0.05), decreased expression level of Rorγt (P<0.05), and less CD4+IL17+cells (P<0.05) compared with control group. Conclusion During the process of CD4+CD62L+T differentiating into Th17 in vitro, IL-2 could facilitate T cell proliferation but inhibit the differentiation of Th17.

Key words: interleukin-2, helper T cell 17, proliferation, differentiation