Objective: To explore the impact of both cigarette smoke extracts (CSE) and CD40-CD40L pathway blocking on mouse myeloid dendritic cells (DCs) inducing CD4(+)T cells differentiation into CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs). METHODS :A combination of recombinant mouse granulocyte-macrophage colony stimulating factor (rmGM-CSF, 40 ng/mL) and recombinant mouse IL-4 (rmIL-4, 10 ng/mL) was applied in vitro to induce the differentiation of BALB/c mouse myeloid monocytes into DCs. DCs were detected for the expression of CD40 molecules through flow cytometry. CD4(+)T cells were sorted out from BALB/c mouse spleen cells with magnetic activated cell sorting technique. Myeloid DCs were co-cultivated with CD4(+)T cells separated from the control-group for 24 hours in the presence of CSE or antagonistic CD40 antibody. CD4(+)CD25(+)Foxp3(+)Tregs were quantified with flow cytometry, and concentrations of IL-10 and IL-6 in cell supernatants were detected with liquid phase chip technology.
Results: The co-cultivation of DCs and CD4(+)T cells promoted CD4(+)CD25(+)Foxp3(+)Tregs differentiation. However, after stimulated by CSE, the number of CD4(+)CD25(+)Foxp3(+)Tregs differentiated by co-cultivation of DCs and CD4(+)T cells was reduced, accompanied by the decrease of IL-10 concentration and the increased of IL-6 concentration. In contrast, with the intervention of antagonistic CD40 antibody, the number of CD4(+)CD25(+)Foxp3(+)Tregs increased, IL-10 concentration rose and IL-6 dropped.
Conclusion: CSE can substantially reduce CD4(+)CD25(+)Foxp3(+)Tregs, but blocking CD40-CD40L pathway in vitro by antagonistic CD40 antibody can promote the process of CD4(+)T cells differentiating into CD4(+)CD25(+)Foxp3(+)Tregs.