title: Effect of IgM fractions with or without rheumatoid factor activity on antigen-antibody reactions.
abstract: The effect of isolated IgM fractions, with or without rheumatoid factor (RF) activity, on reactions between human albumin and rabbit anti-human albumin, human IgG and rabbit anti-human IgG, and tetanus toxoid and human anti-tetanus toxoid was assessed in the antigen excess zone. RF-active fractions increased and RF-negative IgM fractions decreased the amount of free antigen. The immune complexes that were affected by RF IgM fractions differed in composition from those affected by normal IgM fractions.
mesh_terms: D000936:Antigen-Antibody Complex; D000937:Antigen-Antibody Reactions; D006801:Humans; D007106:Immune Sera; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M; D007158:Immunologic Techniques; D012217:Rheumatoid Factor; D012709:Serum Albumin / Q000276:immunology
chemical_list: D000936:Antigen-Antibody Complex; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012709:Serum Albumin; D012217:Rheumatoid Factor