title: ACTH-like activity in immune complexes of patients with oat-cell carcinoma of the lung.
abstract: Immune complexes could be isolated from sera of 7 patients with oat-cell carcinoma of the lung, but not from 5 normal controls, using zonal ultracentrifugation. After ultracentrifugation, fractions containing macromolecular IgG were absorbed on a protein A-sepharose column and the immune complexes were eluted and dissociated by glycin-HCl buffer at pH 3.5. The eluates were tested for the presence of tumour-associated proteins as carcinoembryonic antigen (CEA), non-specific crossreacting antigen (NCA), alpha2 pregnancy associated antigen (alpha2PAG) and isoferritin. Whereas none of these tumour-associated antigens could be demonstrated, an ACTH-like activity was detected in the immune-complex fractions of 4 patients with oat-cell carcinoma, by radioimmuno- and bioassay. Polyacrylamide electrophoresis of an immune-complex fraction from a patient with Cushing syndrome showed ACTH-like activities, with mol. wt of 110,000, 75,000, 30,000 and less than 20,000 (all glycoproteins) indicating the presence of different subfractions of big ACTH.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000368:Aged; D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm / Q000032:analysis; D002272:Carcinoembryonic Antigen / Q000032:analysis; D018288:Carcinoma, Small Cell / Q000276:immunology*; D003480:Cushing Syndrome / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight
chemical_list: D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D002272:Carcinoembryonic Antigen; D000324:Adrenocorticotropic Hormone