Human recombinant interferon‐β influences T helper subset differentiation by regulating cytokine secretion pattern and expression of homing receptors

Type I interferons (IFN) are important regulators of both innate and acquired immunity. We have used an in vitro system of human CD4+ T cell differentiation to determine how IFN‐β influences development of T helper (Th) subsets and homing receptor expression. IFN‐β promoted differentiation of CD4+ T cells that produce low levels of both IFN‐γ and lymphotoxin compared to interleukin (IL)‐12‐derived Th1 CD4+ T cells. IFN‐β inhibited production of Th2 cytokines (IL‐5 and IL‐13) and augmented IL‐12‐mediated IL‐10 secretion. In addition, IFN‐β significantly enhanced L‐selectin expression on CD4+ T cells and synergized with IL‐12 to induce expression of cutaneous lymphocyte‐associated antigen (CLA). This Th1 L‐selectin+, CLA+ phenotype is characteristic of T cells found in normal human skin and suggests a role for type I IFN in the regulation of Th subset differentiation and tissue‐specific homing receptors.