Cutting Edge: Unique T Cells That Recognize Citrullinated Peptides Are a Feature of Protein Immunization

Abstract
Abs against citrullinated proteins are present in patients with rheumatoid arthritis. In this study, we describe a unique cohort of T cells that selectively responded to citrullinated variants of two epitopes of hen egg-white lysozyme, a major and a minor one, bound to the MHC molecule, I-Ak. In addition, we show that when given an intact, unmodified lysozyme protein, dendritic cells and peritoneal macrophages presented citrullinated peptides and stimulated modification-specific T cells. Thus, presentation of citrullinated-peptide-MHC complex is a feature of immune responses to protein Ags.