TY - JOUR
T1 - Locally Produced Complement Fragments C5a and C3a Provide Both Costimulatory and Survival Signals to Naive CD4+ T Cells
AU - Strainic, Michael G.
AU - Liu, Jinbo
AU - Huang, Danping
AU - An, Fengqi
AU - Lalli, Peter N.
AU - Muqim, Nasima
AU - Shapiro, Virginia S.
AU - Dubyak, George R R.
AU - Heeger, Peter S.
AU - Medof, M. Edward
N1 - Funding Information:
This work was supported by NIH grants AI23598 and EY11288 (M.E.M.) and AI43578 (P.S.H.) and an AHA predoctoral fellowship (P.N.L.). The authors thank M. Carroll for C3 −/− mice, C. Gerard for C5ar1 −/− and C3ar1 −/− mice, J. Lambris for C5aR-A, L. Mayo for help on phospho-AKT, K. Shokat for PI-3 kinase inhibitors, A. Larner and A. Weiss for helpful discussion, F. Lin for assisting with tail-vein injections, C. Subauste for help with T. gondii injection, J. Arth and K. Thomas for help with the bacterial keratitis model, and D. Kaplan, M. Lamm, and M. Sy for critical reading.
PY - 2008/3/14
Y1 - 2008/3/14
N2 - Costimulatory signals are critical to T cell activation, but how their effects are mediated remains incompletely characterized. Here, we demonstrate that locally produced C5a and C3a anaphylatoxins interacting with their G protein-coupled receptors (GPCRs), C5aR and C3aR, on APCs and T cells both upstream and downstream of CD28 and CD40L signaling are integrally involved in T cell proliferation and differentiation. Disabling these interactions reduced MHC class II and costimulatory-molecule expression and dramatically diminished T cell responses. Importantly, impaired T cell activation by Cd80-/-Cd86-/- and Cd40-/- APCs was reconstituted by added C5a or C3a. C5aR and C3aR mediated their effects via PI-3 kinase-γ-dependent AKT phosphorylation, providing a link between GPCR signaling, CD28 costimulation, and T cell survival. These local paracrine and autocrine interactions thus operate constitutively in naive T cells to maintain viability, and their amplification by cognate APC partners thus is critical to T cell costimulation.
AB - Costimulatory signals are critical to T cell activation, but how their effects are mediated remains incompletely characterized. Here, we demonstrate that locally produced C5a and C3a anaphylatoxins interacting with their G protein-coupled receptors (GPCRs), C5aR and C3aR, on APCs and T cells both upstream and downstream of CD28 and CD40L signaling are integrally involved in T cell proliferation and differentiation. Disabling these interactions reduced MHC class II and costimulatory-molecule expression and dramatically diminished T cell responses. Importantly, impaired T cell activation by Cd80-/-Cd86-/- and Cd40-/- APCs was reconstituted by added C5a or C3a. C5aR and C3aR mediated their effects via PI-3 kinase-γ-dependent AKT phosphorylation, providing a link between GPCR signaling, CD28 costimulation, and T cell survival. These local paracrine and autocrine interactions thus operate constitutively in naive T cells to maintain viability, and their amplification by cognate APC partners thus is critical to T cell costimulation.
KW - MOLIMMUNO
UR - http://www.scopus.com/inward/record.url?scp=40249116606&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=40249116606&partnerID=8YFLogxK
U2 - 10.1016/j.immuni.2008.02.001
DO - 10.1016/j.immuni.2008.02.001
M3 - Article
C2 - 18328742
AN - SCOPUS:40249116606
SN - 1074-7613
VL - 28
SP - 425
EP - 435
JO - Immunity
JF - Immunity
IS - 3
ER -