Cathepsin L: Critical role in Ii degradation and CD4 T cell selection in the thymus Academic Article Article uri icon


MeSH Major

  • Cell Communication
  • Lymphocyte Activation
  • T-Lymphocytes, Helper-Inducer
  • T-Lymphocytes, Regulatory


  • Degradation of invariant chain (Ii) is a critical step in major histocompatibility complex class II-restricted antigen presentation. Cathepsin L was found to be necessary for Ii degradation in cortical thymic epithelial cells (cTECs), but not in bone marrow (BM)-derived antigen-presenting cells (APCs). Consequently, positive selection of CD4+ T cells was reduced. Because different cysteine proteinases are responsible for specific Ii degradation steps in cTECs and BM-derived APCs, the proteolytic environment in cells mediating positive and negative selection may be distinct. The identification of a protease involved in class II presentation in a tissue-specific manner suggests a potential means of manipulating CD4+ T cell responsiveness in vivo.

publication date

  • April 17, 1998



  • Academic Article


Digital Object Identifier (DOI)

  • 10.1126/science.280.5362.450

PubMed ID

  • 9545226

Additional Document Info

start page

  • 450

end page

  • 3


  • 280


  • 5362