Abstract
AbstractAntibodies of the IgG class to terminal Galα3Gal (IgG anti-αGal) is abundant in human plasma and are reported to bind most sepsis-causing Gram-negative bacteria. However, these seminal findings, made more than two decades ago, have not been reexamined. Our aim was to assess IgG anti-αGal´s pathogen reactivity. We affinity purified IgG anti-αGal from a therapeutic grade normal human IgG pool applying two rounds of positive selection with Galα3Gal-coupled beads and included removal of column matrix reactive antibodies. The purified antibodies were rigorously characterized in terms of specificity and purity in various solid-phase immunoassays. We used flow cytometry to study reactivity against 100 consecutive clinical isolates diagnosed as cause of sepsis in humans. We found that the purified IgG anti-αGal displays high specificity for Galα3Gal. Also, IgG anti-αGal at 5 mg/L bound 56 out of 100 pathogens with predilection for Gram-positive bacteria binding 39 out of 52 strains. We confirm that although IgG anti-αGal comprise a small fraction of the human antibody pool (~0.1%), these antibodies targets an impressively large part of pathogens causing invasive disease.
Funder
This work was supported by an Aarhus University grant to JMBJ, Bloddonorernes Forskningsfond, and Forskningstræningspuljen, Region Midt. The authors declare no competing interests.
Publisher
Springer Science and Business Media LLC
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