Expression of SKAP-HOM in DCs is required for an optimal immune response in vivo

J Leukoc Biol. 2009 Jul;86(1):61-71. doi: 10.1189/jlb.0608344. Epub 2009 Apr 15.

Abstract

The cytosolic adaptor molecule SKAP-HOM, similar to the T cell-specific homologue SKAP55, interacts directly with ADAP, and both molecules are involved in inside-out signaling. Previous studies have shown that in the absence of SKAP-HOM, antigen receptor-triggered integrin-mediated adhesion is impaired severely in B cells but not in T cells. In addition, loss of SKAP-HOM results in a less severe clinical course of EAE. DCs are the most potent APCs and express SKAP-HOM. However, the role of SKAP-HOM in DCs remains unknown. Here, we assessed whether the reduced severity of EAE observed in SKAP-HOM-deficient mice is at least partially a result of an impaired cooperation between APCs and T cells. We demonstrate that migration of LC in vivo and the spontaneous motility of BMDCs in vitro are increased in the absence of SKAP-HOM. In contrast, triggering of the integrin results in a drastic decrease of DC motility and in enhanced actin polymerization in SKAP-HOM-deficient DCs. Furthermore, the antigen-dependent conjugate formed between wild-type T cells and SKAP-HOM(-/-) DCs is delayed in comparison with wild-type DCs. Strikingly, fewer antigen-specific T cells are induced by immunization with SKAP-HOM(-/-) BMDCs as compared with wild-type BMDCs in vivo. Thus, these findings suggest that SKAP-HOM expression in DCs is required for the induction of an optimal immune response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Presenting Cells / immunology
  • Cell Movement / immunology
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism
  • Encephalomyelitis, Autoimmune, Experimental
  • Immunity*
  • Immunological Synapses
  • Integrins
  • Intracellular Signaling Peptides and Proteins / deficiency
  • Intracellular Signaling Peptides and Proteins / immunology*
  • Mice
  • Mice, Knockout
  • T-Lymphocytes / immunology

Substances

  • Integrins
  • Intracellular Signaling Peptides and Proteins
  • src kinase associated phosphoprotein 2