Serpinb9 is a marker of antigen cross-presenting dendritic cells

Publication date: February 2017
Source:Molecular Immunology, Volume 82
Author(s): M.S. Mangan, J. Vega-Ramos, L.T. Joeckel, A.J. Mitchell, A. Rizzitelli, B. Roediger, D. Kaiserman, W.W. Weninger, J.A. Villadangos, P.I. Bird
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.



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