Objective: To investigate the effects of Mycobacterium tuberculosis heat-resistant antigen (MTB-HAg) and anti-TCR γδ monoclonal antibody (mAb) on the induction and differentiation of human IL-17-producing γδT cells under polarization culture conditions.
Methods: From human peripheral blood mononuclear cells, the γδT cells were purified by magnetic-activated cell sorting (MACS) and then stimulated with MTB-HAg or anti-TCRγδ mAb and with or without anti-CD28 mAb, and cultured in the presence or absence of the cytokine cocktails (CK) (IL-1β, IL-6, TGF-β and IL-23) for 10 to 12 days. The polarized cultured γδT cells were collected and re-stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin for 6 hours, and the number of IL-17-producing cells was detected by ELISPOT.
Results: The number of IL-17-producing cells (per 10⁵ γδT cells) in anti-TCRγδ combined with CK group was significantly higher than that in the anti-TCRγδ group. Meanwhile, the IL-17-producing γδT cell number in anti-TCRγδ combined with anti-CD28 group was lower than that in the anti-TCRγδ combined with anti-CD28 and CK group. The IL-17-producing γδT cell number of anti-TCRγδ combined with anti-CD28 and CK group was significantly higher than that in anti-TCRγδ combined with CK group, and that in MTB-HAg combined with anti-CD28 and CK group was significantly lower than that in anti-TCRγδ combined with anti-CD28 and CK group, but higher than that in MTB-HAg combined with anti-CD28 group.
Conclusion: The CK (IL-1β, IL-6, TGF-β and IL-23) required for the differentiation of Th17 cells also induced the differentiation of IL-17⁺ γδT cells after pre-activated by MTB-HAg or anti-TCRγδ antibody, while anti-TCRγδ mAb showed the stronger stimulatory effect than MTB-HAg. In addition, CD28 co-stimulation enhanced the differentiation of IL-17 from activated γδT cells.