Antigen-specific regulation of ige antibodies by non-antigen-specific gd t cells

摘要

We re-examined the observation that gd T cells, when transferred from mice tolerized to an inhaled conventional Ag, suppress the allergic IgE response to this Ag specifically. Using OVA and hen egg lysozyme in crisscross fashion, we confirmed the Ag-specific IgE-regulatory effect of the gd T cells. Although only Vg4+ gd T cells are regulators, the Ag specificity does not stem from specificity of their gd TCRs. Instead, the Vg4+ gd T cells failed to respond to either Ag, but rapidly acquired Ag-specific regulatory function in vivo following i.v. injection of non-T cells derived from the spleen of Ag-tolerized mice. This correlated with their in vivo Ag acquisition from i.v. injected Ag-loaded splenic non-T cells, and in vivo transfer of membrane label provided evidence for direct contact between the injected splenic non-T cells and the Vg4+ gd T cells. Together, our data suggest that Ag itself, when acquired by gd T cells, directs the specificity of their IgE suppression.