Quantification of the Terminal Complement Complex in Human Plasma by an Enzyme‐Linked Immunosorbent Assay Based on Monoclonal Antibodies against a Neoantigen of the Complex

TLDR

The fluid‑phase terminal complement complex (TCC), comprising C5b, C6, C7, C8, C9, and the S‑protein, has recently been detected in normal human plasma using antibodies against native terminal complement components. The study aims to develop a sensitive, specific, and reliable ELISA for quantifying the TCC by employing monoclonal antibodies against a neoantigen of the complex. The assay uses monoclonal antibodies targeting a neoantigen of the TCC to enable sensitive detection in plasma samples. The assay detected TCC in normal plasma and revealed elevated levels in patients with complement activation, confirming prior observations and demonstrating ease of use for large sample sets.

Abstract

The fluid‐phase terminal complement complex (TCC), consisting of the components C5b, C6, C7, C8, C9, and the S‐protein, has recently been detected in normal human plasma by using antibodies against native terminal complement components. Increased amounts of TCC were then found in several patients with in vivo activation of complement. We now describe a sensitive, specific, and reliable enzyme‐linked immunosorbent assay for quantification of the TCC, based on monoclonal antibodies against a neoantigen of the complex. The results indicate that the TCC is present in normal human plasma and in increased amounts in patients with complement activation in vivo, thus confirming previously obtained results. The assay is easy to perform and can be used for examination of large numbers of plasma samples.