International Immunology Advance Access originally published online on April 19, 2007
International Immunology 2007 19(6):719-732; doi:10.1093/intimm/dxm034
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Protein kinase C delta stimulates antigen presentation by Class II MHC in murine dendritic cells
1 Department of Dermatology, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, HIM-660, Boston, MA 02115, USA
2 Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
3 Division of Gastroenterology and Nutrition, Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
4 Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
Correspondence to: M. Boes; E-mail: mboes{at}rics.bwh.harvard.edu
Maturation of dendritic cells (DCs) regulates protein sorting in endosomal compartments to promote the surface expression of molecules involved in T cell activation. MHC Class II complexes are mobilized to the surface via intracellular effector molecules that remain largely unknown. We here show that protein kinase C (PKC) stimulates Class II antigen surface expression, using knock-in mice that express a Class II–green fluorescent protein fusion protein as a read out. Selective inhibition of PKC
counteracts the ability of DCs to stimulate Class II MHC-restricted antigen-specific T cells. Activation of PKC does not affect antigen uptake, peptide loading and surface display of Class I MHC and transferrin receptor in DCs. We show that activation-induced Class II MHC surface expression is dependent on activation of PKC and conclude that this event is pivotal for optimal CD4 T cell activation.
Keywords: antigen presentation/processing, antigens/peptides/epitopes, dendritic cells, rodent
Transmitting editor: C. Terhorst
Received 6 November 2006, accepted 5 March 2007.