Monoclonal antibody M3 used in tissue polypeptide-specific antigen assay for the quantification of tissue polypeptide antigen recognizes keratin 18.
Recently, a new 'specific tissue polypeptide antigen (TPA)' test was introduced and designated tissue polypeptide-specific antigen (TPS); it is based on the monoclonal antibody (MAb) anti-TPS, M3. We have tested the specificity of this antibody by immunocyto- and immunohistochemistry, gel electrophoresis and immunoblotting. MAb M3 bound to intermediate filaments of epithelial cells and revealed a staining pattern identical to cytokeratin (CK) 18-specific MAb (DE-K18) on tissue sections of various human tissues. On immunoblots of proteins extracted from various epithelial cell lines, M3 reacted with a 45-kD protein corresponding to CK18, and on immunoblots of proteins isolated from MCF-7 culture fluid M3 stained three bands, 45, 33 and 29 kD. The same bands were stained with CK18-specific MAb, indicating that they represent CK18 and its degradation products. TPA, used as a tumor marker in clinical diagnoses and follow-up, was shown to be a degradation product of CK 8, 18 and 19. In contrast to TPA, MAb M3 did not stain CK8 and CK19 present on immunoblots.
Bonfrer
J M
JM
Department of Clinical Chemistry, The Netherlands Cancer Institute, (Antoni van Leeuwenhoek Huis), Amsterdam.
Groeneveld
E M
EM
Korse
C M
CM
van Dalen
A
A
Oomen
L C
LC
Ivanyi
D
D
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D004848:Epithelium / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis*; D051379:Mice; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000737:chemistry*; D010455:Peptides / Q000032:analysis*; D011933:Reagent Kits, Diagnostic; D019396:Tissue Polypeptide Antigen; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D010455:Peptides; D011933:Reagent Kits, Diagnostic; D019396:Tissue Polypeptide Antigen; D007633:Keratins