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bioRxiv · 10.1101/2022.08.30.505882

Immunopeptidomics reveals determinants of Mycobacterium tuberculosis antigen presentation on MHC class I

Leddy, O.·White, F.·Bryson, B. D.
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Abstract

CD8+ T cell recognition of Mycobacterium tuberculosis (Mtb)-specific peptides presented on major histocompatibility complex class I (MHC-I) contributes to immunity to tuberculosis (TB), but the principles that govern presentation of Mtb antigens on MHC-I are incompletely understood. In this study, mass spectrometry (MS) analysis of the MHC-I repertoire of Mtb-infected primary human macrophages reveals that substrates of Mtbs type VII secretion systems (T7SS) are overrepresented among Mtb-derived peptides presented on MHC-I. Quantitative, targeted MS shows that ESX-1 activity contributes to presentation of Mtb antigens on MHC-I, consistent with a model in which Mtb T7SS substrates access a cytosolic antigen processing pathway via ESX-1-mediated phagosome permeabilization. Chemical inhibition of proteasome activity, lysosomal acidification, or cysteine cathepsin activity did not block presentation of Mtb antigens on MHC-I, suggesting involvement of other proteolytic pathways or redundancy among multiple pathways. Our study identifies Mtb antigens presented on MHC-I that could serve as targets for TB vaccines, and reveals an important role for T7SS activity in presentation of Mtb antigens on MHC-I.

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Leddy, O., White, F., Bryson, B. D.. 2022-08-30. Immunopeptidomics reveals determinants of Mycobacterium tuberculosis antigen presentation on MHC class I. https://doi.org/10.1101/2022.08.30.505882

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