Polyreactive IgM antibodies in the circulation are masked by antigen binding.
Human plasma containing IgM showed only minimal, if any, reactivity with a panel of antigens as measured by ELISA. In contrast, affinity-purified IgM showed many times more reactivity with the same panel of antigens. When plasma was added back to the affinity-purified IgM, the reactivity of the IgM with antigens was completely inhibited by undiluted plasma and by as much as 40% with as little as a 1:100 dilution of plasma. When the affinity-purified IgM was affinity-purified a second time by passage through antigen-specific columns (e.g., insulin or Fc or beta-galactosidase), the eluted antibodies bound not only to the antigen used for purification, but also to a panel of unrelated antigens, indicating that the antibodies were polyreactive. It is concluded that polyreactive IgM antibodies are present in the circulation but are masked by binding to circulating antigens.
Sigounas
G
G
Laboratory of Oral Medicine, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892.
Kolaitis
N
N
Monell-Torrens
E
E
Notkins
A L
AL
D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions / Q000276:immunology*; D001667:Binding, Competitive / Q000276:immunology; D002846:Chromatography, Affinity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology*
D007075:Immunoglobulin M