Site-specific N-glycan analysis of antibody-binding Fc γ receptors from primary human monocytes.

Site-specific N-glycan analysis of antibody-binding Fc γ receptors from primary human monocytes. Mol Cell Proteomics. 2019 Dec 30;: Authors: Roberts JT, Patel KR, Barb AW Abstract FcγRIIIa (CD16a) and FcγRIIa (CD32a) on monocytes are essential for proper effector functions including antibody dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Indeed, therapeutic monoclonal antibodies (mAbs) that bind FcγRs with greater affinity exhibit greater efficacy. Furthermore, post-translational modification impacts antibody binding affinity, most notably the composition of the asparagine(N)-linked glycan at N162 of CD16a. CD16a is widely recognized as the key receptor for the monocyte response, however the post-translational modifications of CD16a from endogenous monocytes are not described. Here we isolated monocytes from individual donors and characterized the composition of CD16a and CD32a N-glycans from all modified sites. The composition of CD16a N-glycans varied by glycosylation site and donor. CD16a displayed primarily complex-type biantennary N-glycans at N162, however some individuals expressed CD16a V158 with ~20% hybrid and oligomannose types which increased affinity for IgG1 Fc according to surface plasmon resonance binding analyses. The CD16a N45-glycans contain markedly less processing than other sites with >75% hybrid and oligomannose forms. N38 and N74 of CD16a both contain highly processed complex-type N-gly...
Source: Molecular and Cellular Proteomics : MCP - Category: Molecular Biology Authors: Tags: Mol Cell Proteomics Source Type: research