Cell Reports
Volume 25, Issue 11, 11 December 2018, Pages 3110-3122.e6
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Article
Galectin-8 Favors the Presentation of Surface-Tethered Antigens by Stabilizing the B Cell Immune Synapse

https://doi.org/10.1016/j.celrep.2018.11.052Get rights and content
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Highlights

  • Galectin-8 reinforces B cell arrest phases upon antigen recognition in vivo

  • Galectin-8 sustains BCR signaling during recognition of immobilized antigens

  • This enhances lysosome secretion and favors the proteolytic extraction of antigens

  • Galectin-8 improves the capacity of B cells to present antigens to helper T cells

Summary

Complete activation of B cells relies on their capacity to extract tethered antigens from immune synapses by either exerting mechanical forces or promoting their proteolytic degradation through lysosome secretion. Whether antigen extraction can also be tuned by local cues originating from the lymphoid microenvironment has not been investigated. We here show that the expression of Galectin-8—a glycan-binding protein found in the extracellular milieu, which regulates interactions between cells and matrix proteins—is increased within lymph nodes under inflammatory conditions where it enhances B cell arrest phases upon antigen recognition in vivo and promotes synapse formation during BCR recognition of immobilized antigens. Galectin-8 triggers a faster recruitment and secretion of lysosomes toward the B cell-antigen contact site, resulting in efficient extraction of immobilized antigens through a proteolytic mechanism. Thus, extracellular cues can determine how B cells sense and extract tethered antigens and thereby tune B cell responses in vivo.

Keywords

B lymphocytes
immune synapse
Galectin-8
antigen extraction
processing and presentation
cell polarity
mouse immunization

Cited by (0)

10

Present address: Pathogenesis of Vascular Infections Unit, INSERM U1225, Institut Pasteur, 75015 Paris, France

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Present address: CERMES3, INSERM U988, CNRS UMR8211, EHESS, Université Paris Descartes, BP 8, 94801 Villejuif Cedex, France

12

These authors contributed equally

13

These authors contributed equally

14

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