Bacterial Surface Protein L Binds and Inactivates Neutrophil Proteins S100A8/A9

Abstract

Finegoldia magna is an anaerobic bacterial species that is part of the normal human flora on all nonsterile body surfaces, but it is also a significant opportunistic pathogen causing a wide range of infections. Some isolates of F. magna that are more frequently associated with clinical infection express protein L, a surface protein containing multiple homologous domains (B1-B5) that bind Igs through interactions with Ig L chains. The present study shows that the N-terminal A domain of protein L binds S100A8/A9, antibacterial proteins present in large amounts in the cytoplasm of neutrophils, but also extracellularly in tissues during inflammation. As a result, protein L-expressing F. magna are protected against killing by S100A8/A9. Igs and S100A8/A9 were found to interact independently with protein L, demonstrating that this bacterial surface protein is capable of manipulating both adaptive and innate immune defense mechanisms.

Exploitation of Diatom Frustules for Nanotechnology: Tethering Active Biomolecules

“…Here we have demonstrated surface modification using anti-IgY. The direct coupling of anti-IgY to the diatom surface is also of particular interest since IgY (the main low-molecular-weight immunoglobulin present in chicken serum and egg yolk) does not bind to protein A or protein G. [6,7] The attachment of the antibody was demonstrated by probing with a secondary antibody conjugated to an enzyme (HRP).…”

Purification of Native and Recombinant Cobra Venom Factor Using Thiophilic Adsorption Chromatography

“…Large scale expression was performed in roller flasks using OptiMEM (Invitrogen life sciences, Karlsruhe, Germany) supplemented with 4% (v/v) heat-inactivated fetal calf serum, penicillin, and streptomycin. Prior to use fetal calf serum was stripped of bovine IgGs by protein G affinity chromatography [33].…”

Targeted Delivery using Immunoliposomes with a Lipid-Modified Antibody-Binding Protein

“…This protein has its limitations, however, because protein A exhibits poor avidity for some antibody classes, such as mouse IgG 1 and goat IgG 1 , even though most monoclonal antibodies are generated from mouse. In the present study, we utilized three repeats of the Fc-binding domain of streptococcal protein G (C3), which has more IgG-binding versatility than does protein A [16].…”