title: Complement regulation of T cell immunity.
abstract: Results of studies published since 2002 reveal that T cells and antigen-presenting cells (APCs) produce complement proteins. The immune cell-derived, alternative pathway complement components activate spontaneously, yielding local, but not systemic, production of C3a and C5a. These anaphylatoxins bind to their respective G-protein-coupled receptors, C3aR and C5aR, expressed on both partners. The resultant complement-induced T cell activation and APC activation drive T cell differentiation, expansion and survival. Complement deficiency or blockade attenuates T cell-mediated autoimmunity and delays allograft rejection in mice. Increasing complement activation, achieved by genetic removal of the complement regulatory protein decay-accelerating factor, enhances murine T cell immunity and accelerates allograft rejection. The findings support the need for design and testing of complement inhibitors in humans.
authors.affiliation: Department of Medicine, Recanati Miller Transplant Institute and Immunology Institute, Mount Sinai School of Medicine, Box 1243, One Gustave L. Levy Plaza, New York, NY 10029, USA.
authors.forename: Wing-hong
authors.initials: WH
authors.lastname: Kwan
authors.forename: William
authors.initials: W
authors.lastname: van der Touw
authors.forename: Peter S
authors.initials: PS
authors.lastname: Heeger
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D003165:Complement System Proteins / Q000276:immunology*; D006801:Humans; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D003165:Complement System Proteins