Fibrinogen binds IgG antibody and enhances IgG-mediated phagocytosis¹

Article type: Research Article

Authors: Boehm, Tobias K.^{a; *} | DeNardin, Ernesto^{a; b}

Affiliations: [a] Department of Oral Biology, State University of New York at Buffalo, Buffalo, NY, USA | [b] Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, NY, USA

Correspondence: [*] Corresponding author: Tobias K.~Boehm, 210 Foster Hall, SUNY Buffalo, Buffalo, NY 14214-3092, USA. Tel.: +1 716 829 3518; E-mail: tboehm@buffalo.edu

Note: [1] This study is supported by NIH grants DE07926 and DE07034.

Abstract: While Fibrinogen (Fg) and Immunoglobulin G (IgG) are traditionally thought to have separate functions in thrombosis and immune response, recent studies suggest overlapping functions. Here we present evidence that Fibrinogen binds to IgG specifically, and that Fibrinogen-IgG interactions enhance phagocytosis. We demonstrate specific, saturable binding of Fibrinogen to immobilized IgG and its fragments on nitrocellulose or poly-(L)-Lys styrene plates using Biotin/Streptavidin-Horse Radish Peroxidase detection systems. We also demonstrated that GFP-expressing E.coli coated with anti-E.coli antibody (IgG) and Fibrinogen elicit higher rates of phagocytosis than either Fibrinogen or IgG-treated E.coli alone (p < 0.001). We conclude that Fibrinogen enhances phagocytosis and possibly other leukocyte functions in concert with IgGs. This mechanism might focus leukocyte action triggered by fibrinogen towards specific antigens.

Keywords: Acute phase reactants, antibodies, fibrinogen

DOI: 10.3233/HAB-2008-173-401

Journal: Human Antibodies, vol. 17, no. 3-4, pp. 45-56, 2008