Genetic Polymorphism in Proteins of the Complement System / 대한이식학회지

The complement system is a part of the innate immune system that potentiates the ability of antibodies and phagocytic cells to clear microbes and damaged cells. The complement system consists of a number of proteins circulating as inactive precursors. It is stimulated mainly by three pathways: the classical pathway, the alternative pathway, and the lectin pathway. There are many genetic polymorphisms in this system, which can over-activate the immune system. In this study, we collected the polymorphisms reported to over-activate complement cascades that affect the immune system and induce autoimmune diseases.

Application of bispecific antibody against antigen and hapten for immunodetection and immunopurification

We present a bispecific antibody that recognizes an antigen and a hapten and can be applied to various biological assays, including immunoblotting and immunoprecipitation. In immunoblot analysis of serum, an anti-C5 x anti-cotinine bispecific tandem single-chain variable fragment (scFv)-Fc fusion protein and cotinine-conjugated horseradish peroxidase (HRP) generated a clean signal without the high background that was observed in a parallel experiment using HRP-conjugated goat anti-rabbit immunoglobulin G (Fc-specific) antibody. In immunoprecipitation analysis of serum, use of the bispecific tandem scFv-Fc fusion protein and cotinine-crosslinked magnetic beads significantly reduced the amount of protein contaminants compared with a parallel experiment done with protein A agarose beads. In subsequent immunoblot analysis, use of cotinine-HRP as the secondary probe instead of HRP-conjugated goat anti-rabbit IgG (Fc-specific) antibody successfully eliminated the band corresponding to the bispecific tandem scFv-Fc fusion protein.