Regulation of Antigen Export to the Cytosol During Cross-Presentation.

Marine Gros,Sebastian Amigorena

doi:10.3389/fimmu.2019.00041

Marine Gros, Sebastian Amigorena

Open Access

https://doi.org/10.3389/fimmu.2019.00041

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Journal: Frontiers in Immunologie	Publication Date: Jan 28, 2019
Citations: 72	License type: CC BY 4.0

Affiliation: Institute Curie, Inserm

Abstract

Cross-priming refers to the induction of primary cytotoxic CD8+ T cell responses to antigens that are not expressed in antigen presenting cells (APCs) responsible for T cell priming. Cross-priming is achieved through cross-presentation of exogenous antigens derived from tumors, extracellular pathogens or infected neighboring cells on Major Histocompatibility Complex (MHC) class I molecules. Despite extensive research efforts to understand the intracellular pathways involved in antigen cross-presentation, certain critical steps remain elusive and controversial. Here we review recent advances on antigen cross-presentation, focusing on the mechanisms involved in antigen export to the cytosol, a crucial step of this pathway.

Highlights

Dendritic cells (DCs) play a central role in immune homeostasis by linking innate sensing to adaptive immune responses
The generally accepted paradigm supposed that exogenous antigens were exclusively presented via Major Histocompatibility Complex (MHC)-II molecules to CD4+ T cells, while endogenous cytosolic antigens, derived from self or foreign proteins, were loaded on MHC-I, thereby leading to naïve cytotoxic CD8+ T cell activation
This apparent contradiction was resolved by the discovery of cross-presentation, a process enabling the delivery of exogenous antigens to the MHC-I pathway for cross-priming CD8+ cytotoxic T cell responses [1, 2]

Summary

Introduction

Dendritic cells (DCs) play a central role in immune homeostasis by linking innate sensing to adaptive immune responses. These observations led to the first description of the “vacuolar pathway.” After internalization, antigens remain confined in intracellular compartments, where they undergo lysosomal degradation, a process largely dependent on cathepsin S activity [12], and followed by loading onto post-Golgi MHC-I molecules.

Results

Conclusion