Normally Occurring Human Anti-GM₁Immunoglobulin M Antibodies and the Immune Response to Bacteria

Abstract

Anti-GM 1 antibodies of the immunoglobulin M (IgM) isotype are normal components of the antibody repertoire of adult human serum. Using a sensitive high-performance thin-layer chromatography (HPTLC) immunostaining assay, we found that these antibodies were absent in the umbilical vein and children <1 month of age but could be detected after 1 month of age. Although most of the children older than 6 months of age were positive, there were still a few negative children. The appearance of anti-GM 1 IgM antibodies showed a perfect concordance with two well-characterized antibacterial antibodies, anti-Forssman and antiblood group A, which indicates a similar origin. We also studied IgM reactivity with lipopolysaccharides (LPSs) from gram-negative bacteria isolated from stool samples from healthy babies and from Escherichia coli HB101 in serum from individuals of different ages. We found a positive reaction with both LPSs in all the children more than 1 month of age analyzed, even in those that were negative for anti-GM 1 antibodies. Anti-GM 1 IgM antibodies were purified from adult serum by affinity chromatography and tested for the ability to bind LPSs from different bacteria. This highly specific preparation showed reactivity only with LPS from a strain of Campylobacter jejuni isolated from a patient with diarrhea. We conclude that normally occurring IgM antibodies are generated after birth, probably during the immune defense against specific bacterial strains.

Ganglioside Molecular Mimicry and Its Pathological Roles in Guillain-Barré Syndrome and Related Diseases

“…Alaniz et al (1) presented evidence indicating a similar origin for immunoglobulin M (IgM) anti-GM1 antibodies in healthy humans. Anti-GM1 antibodies were purified from adult sera by affinity chromatography, and their ability to bind LPSs from different bacteria was tested.…”

Neurological disorders-associated anti-glycosphingolipid IgG-antibodies display differentially restricted IgG subclass distribution

“…In the present work, we characterized the antibody immune response (IgM, total IgG and IgG subclasses) against diverse non-self and self glycosphingolipids in a cohort of patients with neurological disorders. Parallel evaluation of the humoral immune response against glycosphingolipids carrying either non-self glycans or self glycans allowed comparisons between both types of responses, where anti-non-self glycan IgM antibodies are considered anti-bacterial antibodies 4,5,35 .…”

Anti‐NeuGcGM3 reactivity: a possible role of natural antibodies and B‐1 cells in tumor immunosurveillance

“…Table summarizes some properties of the antitumor monoclonal antibodies discussed in this paper. Furthermore, naturally occurring antibodies have also been shown to bind glycolipid molecules called gangliosides …”