title: Occurrence of slowly sedimenting components with mu chain antigenicity in normal adult and cord serum.
abstract: The occurrence of trace amounts of slowly sedimenting components with mu chain antigenicity was investigated in 8 normal adult sera and 4 sera from cord blood of new-born infants. Separation of these components from 19S IgM was obtained by density gradient ultracentrifugation. The fractions were studied by radioimmunoassay. The results suggest that slowly sedimenting components with mu chain antigenicity occur in normal adult serum in amounts located in the mug/ml range. Several components sedimenting with various speeds were identified, although their sedimentation coefficients were not measured. This fact suggests that not only the already described 7S IgM monomer exists in normal blood but that other modes of association between mu and L chains or mu chains fragments also occur. Sera from cord blood showed patterns similar to that of adults.
mesh_terms: D000327:Adsorption; D000328:Adult; D000818:Animals; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D000939:Epitopes; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D006801:Humans; D007106:Immune Sera / Q000302:isolation & purification; D007115:Immunization Schedule; D005779:Immunodiffusion; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis* / Q000302:isolation & purification; D007148:Immunoglobulin mu-Chains; D007231:Infant, Newborn; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D008968:Molecular Conformation; D011817:Rabbits; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D000939:Epitopes; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D007457:Iodine Radioisotopes