PURIFICATION AND CHARACTERIZATION OF CARCINOEMBRYONIC ANTIGEN-RELATED ANTIGENS IN NORMAL ADULT FECES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (2) , 713-720
Abstract
Purification of carcinoembryonic antigen (CEA)-related antigens in normal human feces revealed that, besides nonspecific cross-reacting antigen (fecal NCA), there are 3 other molecular species of CEA-related antigens which have been inclusively called normal fecal antigen (NFA). These were designated normal fecal antigen 1 (NFA-1), normal fecal antigen 2 (NFA-2) and normal fecal cross-reacting antigen (NFCA). All antigens were glycoprotein in nature and migrated electrophoretically in the .beta. region. Their MW were estimated to be 20,000-30,000 for NFA-1, 160,000-170,000 for NFA-2 and 80,000-90,000 for NCA. NFA-2 had amino acid and carbohydrate compositions similar to those of CEA. Immunodiffusion analyses of antigenic determinants indicate that CEA and NFA-2 can be divided into 4 antigenic moieties: the first is distinctive for CEA (cancer determinant) or NFA-2 (NFA-2-distinctive determinant); the 2nd one corresponds to NFA-1 (NFA-1 determinant); and the remaining 2 moieties are present on NFCA, one of which is characteristic for NFCA (NFCA determinant) and the other of which is shared with NCA (NCA-common determinant).