MHC class II molecules on the move for successful antigen presentation

EMBO J. 2008 Jan 9;27(1):1-5. doi: 10.1038/sj.emboj.7601945. Epub 2007 Nov 29.


Major histocompatibility complex class II (MHC II) molecules are targeted to endocytic compartments, known as MIIC, by the invariant chain (Ii) that is degraded upon arrival in these compartments. MHC II acquire antigenic fragments from endocytosed proteins for presentation at the cell surface. In a unique and complex series of reactions, MHC II succeed in exchanging a remaining fragment of Ii for other protein fragments in subdomains of MIIC before transport to the cell surface. Here, the mechanisms regulating loading and intracellular trafficking of MHC II are discussed.

Publication types

  • Review

MeSH terms

  • Animals
  • Antigen Presentation / immunology*
  • Antigen-Presenting Cells / immunology*
  • Antigen-Presenting Cells / metabolism*
  • Cell Compartmentation / immunology
  • Endocytosis / immunology
  • Histocompatibility Antigens Class II / immunology*
  • Histocompatibility Antigens Class II / metabolism*
  • Humans
  • Protein Transport / immunology


  • Histocompatibility Antigens Class II