Human mucosal-associated invariant T (MAIT) cells possess capacity for B cell help

J Leukoc Biol. 2017 Nov;102(5):1261-1269. doi: 10.1189/jlb.4A0317-116R. Epub 2017 Aug 14.

Abstract

Mucosal-associated invariant T (MAIT) cells are an innate-like T cell subset, restricted by the nonclassic MHC class I-related protein MR1 and enriched at mucosal sites. Human studies have shown an association between MAIT cells and pathogen-specific antibody responses. In this study, we investigate the effect of human MAIT cells on B cells ex vivo. We found that supernatants from microbe- or cytokine-stimulated MAIT cells, when added to purified autologous B cells, increase frequencies of plasmablasts and promote IgA, IgG, and IgM production. We found effects to be mostly MR1-dependent and that the increases in plasmablasts are likely a result of increased differentiation from memory B cells. Furthermore, microbe-activated MAIT cell supernatant contains multiple cytokines known to stimulate B cells, including IL-6, -10, and -21. This study thus provides the first direct evidence of a newly identified role of MAIT cells in providing help to B cells.

Keywords: B cell help; MR-1; antibody; plasmablast.

MeSH terms

  • B-Lymphocytes / cytology
  • B-Lymphocytes / immunology*
  • Cell Communication / immunology*
  • Cell Separation
  • Coculture Techniques
  • Escherichia coli / chemistry
  • Escherichia coli / drug effects
  • Escherichia coli / immunology
  • Formaldehyde / chemistry
  • Formaldehyde / toxicity
  • Gene Expression
  • Gene Expression Regulation / immunology*
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / immunology*
  • Humans
  • Immunity, Mucosal*
  • Immunoglobulin A / biosynthesis
  • Immunoglobulin G / biosynthesis
  • Immunoglobulin M / biosynthesis
  • Immunologic Memory
  • Interferon-gamma / genetics
  • Interferon-gamma / immunology
  • Interleukin-10 / genetics
  • Interleukin-10 / immunology
  • Interleukin-6 / genetics
  • Interleukin-6 / immunology
  • Interleukins / genetics
  • Interleukins / immunology
  • Lymphocyte Activation
  • Minor Histocompatibility Antigens / genetics
  • Minor Histocompatibility Antigens / immunology*
  • Mucosal-Associated Invariant T Cells / cytology
  • Mucosal-Associated Invariant T Cells / immunology*
  • Polymers / chemistry
  • Polymers / toxicity
  • Primary Cell Culture
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • Histocompatibility Antigens Class I
  • IL10 protein, human
  • IL6 protein, human
  • Immunoglobulin A
  • Immunoglobulin G
  • Immunoglobulin M
  • Interleukin-6
  • Interleukins
  • MR1 protein, human
  • Minor Histocompatibility Antigens
  • Polymers
  • Tumor Necrosis Factor-alpha
  • Interleukin-10
  • Formaldehyde
  • Interferon-gamma
  • interleukin-21
  • paraform