[PDF][PDF] Macroautophagy proteins control MHC class I levels on dendritic cells and shape anti-viral CD8+ T cell responses

M Loi, A Müller, K Steinbach, J Niven, RB da Silva… - Cell reports, 2016 - cell.com
M Loi, A Müller, K Steinbach, J Niven, RB da Silva, P Paul, LA Ligeon, A Caruso…
Cell reports, 2016cell.com
The macroautophagy machinery has been implicated in MHC class II restricted antigen
presentation. Here, we report that this machinery assists in the internalization of MHC class I
molecules. In the absence of the autophagy factors Atg5 and Atg7, MHC class I surface
levels are elevated due to decreased endocytosis and degradation. Internalization of MHC
class I molecules occurs less efficiently if AAK1 cannot be recruited via Atg8/LC3B. In the
absence of Atg-dependent MHC class I internalization, dendritic cells stimulate CD8+ T cell …
Summary
The macroautophagy machinery has been implicated in MHC class II restricted antigen presentation. Here, we report that this machinery assists in the internalization of MHC class I molecules. In the absence of the autophagy factors Atg5 and Atg7, MHC class I surface levels are elevated due to decreased endocytosis and degradation. Internalization of MHC class I molecules occurs less efficiently if AAK1 cannot be recruited via Atg8/LC3B. In the absence of Atg-dependent MHC class I internalization, dendritic cells stimulate CD8+ T cell responses more efficiently in vitro and in vivo. During viral infections, lack of Atg5 results in enhanced influenza- and LCMV-specific CD8+ T cell responses in vivo. Elevated influenza-specific CD8+ T cell responses are associated with better immune control of this infection. Thus, the macroautophagy machinery orchestrates T cell immunity by supporting MHC class II but compromises MHC class I restricted antigen presentation.
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