Cis interaction between sialylated FcγRIIA and the αI-domain of Mac-1 limits antibody-mediated neutrophil recruitment

Gurpanna Saggu, Koshu Okubo, Yunfeng Chen, Ravi Vattepu, Naotake Tsuboi, Florencia Rosetti, Xavier Cullere, Nathaniel Washburn, Suhail Tahir, Aaron M. Rosado, Steven M. Holland, Robert M. Anthony, Mehmet Sen, Cheng Zhu, Tanya N. Mayadas

Research output: Contribution to journalArticlepeer-review

Abstract

Vascular-deposited IgG immune complexes promote neutrophil recruitment, but how this process is regulated is still unclear. Here we show that the CD18 integrin Mac-1, in its bent state, interacts with the IgG receptor FcγRIIA in cis to reduce the affinity of FcγRIIA for IgG and inhibit FcγRIIA-mediated neutrophil recruitment under flow. The Mac-1 rs1143679 lupus-risk variant reverses Mac-1 inhibition of FcγRIIA, as does a Mac-1 ligand and a mutation in Mac-1’s ligand binding αI-domain. Sialylated complex glycans on FcγRIIA interact with the αI-domain via divalent cations, and this interaction is required for FcγRIIA inhibition by Mac-1. Human neutrophils deficient in CD18 integrins exhibit augmented FcγRIIA-dependent recruitment to IgG-coated endothelium. In mice, CD18 integrins on neutrophils dampen IgG-mediated neutrophil accumulation in the kidney. In summary, cis interaction between sialylated FcγRIIA and the αI-domain of Mac-1 alters the threshold for IgG-mediated neutrophil recruitment. A disruption of this interaction may increase neutrophil influx in autoimmune diseases.

Original languageEnglish (US)
Article number5058
JournalNature communications
Volume9
Issue number1
DOIs
StatePublished - Dec 1 2018
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy

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