title: An IgM monoclonal protein with multiple serological specificities.
abstract: An IgM lambda M-component with a false Wasserman reaction and 'false' rheumatoid factor activity from a patient suffering from a well-differentiated lymphocytic lymphoma is presented. The monoclonal protein showed antibody activity against cardiolipin and cross-reacted with acryl particles, not with human IgG. Both these activities were found in the Fab fragment. The reduction of the 19S IgM to 7S IgM subunits was responsible for a strong decrease in activity. The importance of the IgM quaternary structure in determining antibody affinity is emphasized.
mesh_terms: D000179:Acrylates; D000915:Antibody Affinity; D001666:Binding Sites, Antibody; D002308:Cardiolipins / Q000276:immunology; D003429:Cross Reactions; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007141:Immunoglobulin Fc Fragments / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology*; D007146:Immunoglobulin lambda-Chains; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology*; D012217:Rheumatoid Factor
chemical_list: D000179:Acrylates; D002308:Cardiolipins; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007075:Immunoglobulin M; D007146:Immunoglobulin lambda-Chains; D012217:Rheumatoid Factor