Continuous expression of CD83 on activated human CD4(+) T cells is correlated with their differentiation into induced regulatory T cells

CD83 is a widely recognized surface marker for mature dendritic cells, which are essential for priming naïve CD4(+) T cells into effector cells. However, CD83 is also expressed on activated CD4(+) T cells, which remains an enigma in T-cell mediated immunity. Therefore, the identification of the biological features and regulation of the expression of CD83 on activated CD4(+) T cells is important in understanding the function of CD83 in the adaptive immune response. The present study revealed a time-dependent manner of the expression of CD83 on anti-CD3/CD28-stimulated human CD4(+) T cells, which is characterized by the maximum expression at day 2 and a significant decrease at day 3. The reduced expression is not a result of a reduced rate of cell proliferation. The activation of interleukin-2 and secretion of interferon-γ accumulated progressively from day 1 to 3. Of note, sustained expression of CD83 was observed when CD4(+) T cells were induced by transforming growth factor-β to differentiate into CD4(+)CD25(+) forkhead box P3(+) regulatory T (iTreg) cells. Confocal immunofluorescence microscopy analysis demonstrated that CD83 was highly co-localized with CD25 on activated CD4(+) T cells. In conclusion, the findings of the present study suggested that the continuous expression of CD83 on activated human CD4(+) T cells is correlated with their differentiation into iTreg cells.