Serpinb9 is a marker of antigen cross-presenting dendritic cells

Mol Immunol. 2017 Feb;82:50-56. doi: 10.1016/j.molimm.2016.12.011. Epub 2016 Dec 24.


Serpinb9 (Sb9, also called Spi6) is an intracellular inhibitor of granzyme B (grB) that protects cytotoxic lymphocytes from grB-mediated death. In addition, Sb9 is also expressed in accessory immune cells, including dendritic cells (DCs), although its role is debated. Recently, we have demonstrated that Sb9 plays a grB-independent role in cross-presentation of antigens by CD8+ DCs. Here, using a mouse line expressing green fluorescent protein knocked in under the control of the Sb9 promoter, we demonstrate that Sb9 expression is highest in those tissue-resident and migratory DC subsets capable of cross-presentation. Further, we show that CD8+ DCs can be divided into two subsets based on Sb9 expression, and that only the subset expressing higher levels of Sb9 is capable of cross-presentation. These findings add support for role for Sb9 cross-presentation, and indicate that high Sb9 expression is a novel marker of cross-presentation capable DCs.

Keywords: Cross-presentation; DCs; Dendritic cell; Granzyme B; SPI6; Serpinb9.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cross-Priming / immunology*
  • Dendritic Cells / immunology*
  • Female
  • Flow Cytometry
  • Gene Knock-In Techniques
  • Male
  • Membrane Proteins / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Serpins / immunology*


  • Membrane Proteins
  • Serpins
  • Serpinb9 protein, mouse