C1 Inhibitor Polyclonal Antibody

Plasma protease C1 inhibitor (C1 inhibitor) is a secreted plasma glycoprotein and member of the serine protease inhibitor (SERPIN) family.^1,2 It is composed of an N-terminal domain and a serpin domain, which contains a reactive center loop (RCL).² The RCL of C1 inhibitor mimics the target protease substrates and, upon cleavage, inactivates proteases via an irreversible covalent bond with the protease active site serine. C1 inhibitor targets several serine proteases, including complement 1r (C1r) and C1s, Factor XII, thrombin, and plasmin. It is involved in vascular permeability, extracellular matrix interactions, recognition of pathogens such as bacteria and parasites, ischemia-reperfusion injury, and transplant rejection. Knockout of the gene encoding C1 inhibitor, Serping1, increases vascular permeability in mice.³ Mutations in SERPING1 are associated with hereditary angioedema (HAE), and plasma levels of C1 inhibitor are increased in patients with COVID-19.^4,5 Formulations containing recombinant human C1 inhibitor have been used in the prophylaxis of angioedema attacks. Cayman’s C1 Inhibitor Polyclonal Antibody can be used for ELISA, immunohistochemistry paraffin (IHC-P), and Western blot (WB) applications. The antibody recognizes C1 inhibitor at 56 kDa from human samples.

WARNING This product is not for human or veterinary use.

1. Verpy, E., Couture-Tosi, E., Eldering, E., et al. Crucial residues in the carboxy-terminal end of C1 inhibitor revealed by pathogenic mutants impaired in secretion or function. J. Clin. Invest. 95(1), 350-359 (1995).

2. Davis, r., A.E., Lu, F., and Mejia, P. C1 inhibitor, a multi-functional serine protease inhibitor. Thromb. Haemost. 104(5), 886-893 (2010).

3. Han, E.D., MacFarlane, R.C., Mulligan, A.N., et al. Increased vascular permeability in C1 inhibitor-deficient mice mediated by the bradykinin type 2 receptor. J. Clin. Invest. 109(8), 1057-1063 (2002).

4. Xu, Y.-Y., Zhi, Y.-X., Yin, J., et al. Mutational spectrum and geno-phenotype correlation in Chinese families with hereditary angioedema. Allergy 67(11), 1430-1436 (2012).

5. Hausburg, M.A., Williams, J.S., Banton, K.L., et al. C1 esterase inhibitor-mediated immunosuppression in COVID-19: Friend or foe? Clin. Immunol. Commun. 2, 83-90 (2022).