Premium
N‐glycan composition impacts CD16A structure and antibody binding on natural killer cells
Author(s) -
Barb Adam W,
Patel Kashyap R,
Roberts Jacob T,
Subedi Ganesh P
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.952.4
Subject(s) - glycosylation , glycan , antibody , chemistry , glycoprotein , biochemistry , biology , immunology
Natural killer (NK) cells express CD16A (Fc γαμμα receptor IIIa) to destroy immunoglobulin G (IgG)‐coated particles. IgG1 recognition represents a fundamental process in protective immunity, autoimmune diseases and therapeutic monoclonal antibody efficacy. Despite this central role affecting multiple processes, significant questions regarding the CD16A – IgG1 interaction remain. CD16A is a membrane bound glycoprotein with five asparagine‐linked (N)‐glycosylation sites. Of the five N‐glycosylation sites on CD16A, two (Asn45 and Asn162) are central to function as an antibody receptor. Recent discoveries from our laboratory expose an unexpected role for CD16A N‐glycosylation in antibody binding. CD16A bearing mannose‐type N‐glycans binds the crystallizable fragment (Fc) of IgG1 with a 10‐fold higher affinity than CD16A with complex‐type N‐glycans. The N‐glycan at Asn162 of CD16A is primarily responsible for this surprising effect. Studies by solution nuclear magnetic resonance spectroscopy reveal the CD16A structure is dependent upon N‐glycan composition. A structure of the N‐glycosylated CD16A:IgG1 Fc complex solved by x‐ray crystallography coupled with extensive molecular dynamics simulations reveals a role for the mannose type‐N‐glycans in high affinity antibody recognition. This presentation will also discuss glycan analysis of CD16A from primary human cells and how these unexpected glycoforms impact antibody binding in situ. Support or Funding Information NIH R01‐GM115489 (NIGMS)Structure of the IgG1 Fc:CD16A complex solved by x‐ray crystallography