Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant.

ABSTRACT: Repeated mRNA COVID-19 vaccination increases spike-specific immunoglobulin G4 (IgG4) titers. Here, we characterized the influence of increased IgG4 titers on a range of Fc-mediated responses. Elevated spike-specific IgG4 reduced binding to FcγRIIIa and decreased antibody-dependent cellular cytotoxicity. However, in individuals with lower total spike-specific IgG, IgG4 acted in synergy with other IgG subclasses to improve FcγRI and FcγRIIa binding and consequently antibody-dependent cellular phagocytosis. Furthermore, this trend was more pronounced with more recent SARS-CoV-2 variants where vaccination induced comparably lower total spike-specific titers. These observations were further confirmed by in silico modeling where antibody subclass concentrations and FcγR polymorphisms were modula

SUBMITTER: Aurelia LC 

PROVIDER: S-EPMC11864192 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature