IgA, IgA receptors, and their anti-inflammatory properties

Curr Top Microbiol Immunol. 2014:382:221-35. doi: 10.1007/978-3-319-07911-0_10.

Abstract

Immunoglobulin A (IgA) is the most abundantly produced antibody isotype in mammals. The primary function of IgA is to maintain homeostasis at mucosal surfaces and play a role in immune protection. IgA functions mainly through interaction with multiple receptors including IgA Fc receptor I (FcαRI), transferrin receptor 1 (CD71), asialoglycoprotein receptor (ASGPR), Fcα/μR, FcRL4, and DC-SIGN/SIGNR1. In this review we discuss recent data demonstrating anti-inflammatory functions of IgA through two receptors, the FcαRI and DC-SIGN/SIGNR1 interactions in the regulation of immunity. Serum monomeric IgA is able to mediate an inhibitory signal following the interaction with FcαRI. It results in partial phosphorylation of its FcRγ-ITAM and the recruitment of the tyrosine phosphatase SHP-1, which induces cell inhibition following the formation of intracellular clusters named inhibisomes. In contrast, cross-linking of FcαRI by multimeric ligands induces a full phosphorylation of the FcRγ-ITAM leading to the recruitment of the tyrosine kinase Syk and cell activation. In addition, secretory IgA can mediate a potent anti-inflammatory function following the sugar-dependent interaction with SIGNR1 on dendritic cells which induces an immune tolerance via regulatory T cell expansion. Overall, the anti-inflammatory effect of serum and secretory IgA plays a crucial role in the physiology and in the prevention of tissue damage in multiple autoimmune and inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Cell Adhesion Molecules / physiology
  • Humans
  • Immunoglobulin A / chemistry
  • Immunoglobulin A / physiology*
  • Immunoglobulin A, Secretory / physiology
  • Inflammation / prevention & control*
  • Lectins, C-Type / physiology
  • Receptors, Cell Surface / physiology
  • Receptors, Fc / chemistry
  • Receptors, Fc / physiology*

Substances

  • Cell Adhesion Molecules
  • DC-specific ICAM-3 grabbing nonintegrin
  • IgA receptor
  • Immunoglobulin A
  • Immunoglobulin A, Secretory
  • Lectins, C-Type
  • Receptors, Cell Surface
  • Receptors, Fc