A high-throughput, bead-based, antigen-specific assay to assess the ability of antibodies to induce complement activation

TLDR

The complement system is essential for innate immunity, mediating both non‑specific pathogen killing and antigen‑specific recruitment via complement‑fixing antibodies, yet existing assays lack high‑throughput, sample‑sparing capabilities. This study introduces a high‑throughput, sample‑sparing, bead‑based assay to assess antigen‑specific antibody‑dependent complement activation against virtually any antigen. By optimizing buffer composition, immune complex kinetics, and complement source, the authors developed a robust, flexible platform for analyzing antibody‑dependent complement deposition (ADCD). The resulting assay provides a simple, adaptable tool for profiling antibody‑dependent complement activation across diverse pathogens and diseases.

Abstract

The complement system plays a critical role in innate immune defense against pathogens, both via non-specific direct pathogen recognition and killing or via antigen-specific indirect recruitment by complement fixing antibodies. While various assays for measuring complement activation have been developed, few provide a high-throughput, sample-sparing approach to interrogate the qualitative differences in the ability of antibodies to drive complement activation. Here we present a high-throughput, sample-sparing, bead-based assay to evaluate antigen-specific antibody-dependent complement activation against nearly any antigen. Optimization of buffer composition, kinetics of immune complex formation, as well as complement source all contribute critically to the development of a robust, highly flexible and high-throughput approach to analyze antibody-dependent complement deposition (ADCD). Thus, the optimized bead-based, antigen-specific assay represents a simple, highly adaptable platform to profile antibody-dependent complement activation across pathogens and diseases.