Identification and characterization of latency-associated peptide-expressing γδ T cells

gamma delta T cells are a subset of lymphocytes specialized in protecting the host against pathogens and tumours. Here we describe a subset of regulatory gamma delta T cells that express the latency-associated peptide (LAP), a membrane-bound TGF-beta 1. Thymic CD27 + IFN-gamma + CCR9 + alpha(4)beta(7) + TCR gamma delta + cells migrate to the periphery, particularly to Peyer's patches and small intestine lamina propria, where they upregulate LAP, downregulate IFN-gamma via ATF-3 expression and acquire a regulatory phenotype. TCR gamma delta + LAP + cells express antigen presentation molecules and function as antigen presenting cells that induce CD4 + Foxp3 + regulatory T cells, although TCR gamma delta + LAP + cells do not themselves express Foxp3. Identification of TCR gamma delta + LAP + regulatory cells provides an avenue for understanding immune regulation and biologic processes linked to intestinal function and disease.