title: Ultrastructural study of human IgG and IgG-IgM crystalcryoglobulins.
abstract: Thirty human cryoglobulin precipitates obtained from 21 patients were fixed and examined by electron microscopy; following biochemical isolation and identification. This study showed that the fine structure of cryoprecipitates depends on the involved immunoglobulins and on their respective quantities. Monoclonal IgG kappa 1 or 3 cryoglobulins with antibody activity form crystalling precipitates of 22-nm diameter rods and annuli. When polyclonal, they form 6-nm-wide filaments. Mixed IgG and IgM cryoprecipitates appear as cylindric and annular bodies with an internal diameter of 12 nm and a total diameter of 62 nm. When IgM predominates over IgG, globular condensations with a diameter of 30 nm are seen. Mixtures in which the IgG is more abundant than the IgM include fingerprint-like periodic condensations.
mesh_terms: D000906:Antibodies; D011232:Chemical Precipitation; D003450:Cryoglobulins / Q000032:analysis; D005921:Glomerulonephritis / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007945:Leukemia, Lymphoid / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008854:Microscopy, Electron; D009101:Multiple Myeloma / Q000276:immunology; D011487:Protein Conformation
chemical_list: D000906:Antibodies; D003450:Cryoglobulins; D007074:Immunoglobulin G; D007075:Immunoglobulin M