title: Immunobiochemical characterization of the antigen detected by monoclonal antibody IND.64. Evidence that IND.64 reacts with the cell proliferation associated nuclear antigen previously defined by Ki-67.
abstract: The immunohistochemical characteristics of the monoclonal antibody IND.64 are very similar to those of the monoclonal antibody Ki-67. The aim of this study was to further characterize this new antibody and to compare it with Ki-67 using immunobiochemical methods. Our results demonstrate that the similarity between the antibodies holds true even at the molecular level. Immunoblot analysis of IM-9-cell lysates with both antibodies showed a double band with apparent molecular weights of 395 kD and 345 kD, respectively. Competition ELISAs using a synthetic peptide derived from the thus far determined Ki-67 cDNA sequence as competitor, indicate that IND.64 may recognize the same epitope as Ki-67. The IND.64 epitope resides at least within a 20 amino acid sequence which also contains the Ki-67 epitope. Since IND.64 is of the IgG2b subclass, while Ki-67 is of the IgG1 subclass, the two antibodies may be useful for double immunostaining. In addition, IND.64 may help in determining the still unknown function of the antigen it recognizes.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D002455:Cell Division; D002467:Cell Nucleus / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins / Q000276:immunology*; D009687:Nuclear Proteins / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins