A Soluble Antigen-Specific Factor from CD4+CD25+ T Cells of OVA Tolerant Mice Inducing OVA-Specific Peripheral Tolerance Independently in vivo
CD4+CD25+ T cells played a critical role in the establishment and maintenance of peripheral tolerance via adoptive transfer. However, whether one or more molecules in CD4+CD25+ T cells that could independently mediate peripheral tolerance was disputed by worldwide researchers. In the present study, one soluble antigen-specific factor was extracted from splenic lymphocytes lysates of OVA-tolerant mice (named OVA Immune Tolerance Factor, OVA-ITF) with molecular mass <3 ku which could establish OVA-specific immune tolerance in recipient mice via transfer treated and induce the same effect of peripheral tolerance as those of splenic lymphocytes from OVA-tolerant mice. Treated with OVA-ITF to naive BALB/c mice resulted in significant suppression of DTH reaction and T cell proliferation in an antigen-specific manner as well as a significant increase in the percentage of CD4+CD25+ T cells within the CD4+ T cell subset in peripheral blood. Present study showed that OVA-TIF was produced by CD4+CD25+ T cell subset and could induce OVA-specific peripheral tolerance independently in vivo with TGF-β1 as its main suppressive cytokine in recipient mice. These results suggested that OVA-TIF is a novel, low MW factor and totally different from other suppressive components reported previously which have important implications for expanding new potential therapeutic routes of prevention and control of graft rejection, autoimmune and related diseases.