Specific biochemical and immunological properties of some water-soluble glycoproteins produced by rat gastric mucosal scrapings in vitro

Immunoelectrophoretic pattern of native mucosal intracellular glycoproteins of hog healthy and drug-intoxicated stomachs and of hog body fluids

Naturally occurring glycoproteins have been extracted from fundic and antral mucosal tissue of the hog stomach by means of nondegrading techniques. Major and retarded glycoprotein fractions separated by gel filtration were further dissociated from appreciable amounts of noncovalently bound proteins by CsCl density gradient centrifugation. Antisera to glycoprotein fractions of fundic and antral regions of the stomach were prepared in rabbits. The major fractions from both gastric regions have similar molecular mass (approximately 2 x 10(6)), sedimentation coefficient (approximately 31.5 s), and specific viscosity (approximately 1.6). Purified fractions from each region were further separated into two subfractions by affinity chromatography on wheat germ lectin. Glycoprotein subfractions from antrum and fundus differ appreciably in their carbohydrate and amino acids content, share antigenic determinants, but do not cross-react with anti-hog serum protein antisera. Further diversity in native mucin glycoproteins was observed by the use of one-(D) and two-dimensional (2D) immunoelectrophoresis; subfractions that cross-react with specific anti-hog gastric glycoproteins were found to contain three or more components. D-Immunoelectrophoretic analyses demonstrated (1) in vivo degradation of glycoprotein components of the major fundic fraction isolated from mucosal tissue of alcohol/acetyl salicylate-intoxicated hog stomachs and (2) in vitro catabolism of major fundic glycoproteins by corresponding mitochondrial lysosomal (ML) acid hydrolases. Furthermore, 2D-immunoelectrophoretic analyses showed that (1) hog synovial fluid and plasma proteins have similar prosthetic moieties as either reacted with anti-hog serum proteins antisera. Nonetheless, locations, shapes, and staining intensities of the immunoprecipitate lines differed, which is indicative of different structures of the carbohydrate moieties of components of synovial fluid and plasma proteins, and (2) only a minor fraction of hog cerebrospinal fluid cross-reacted with anti-hog serum protein antisera. This is contrary to the generally accepted deduction based on high-resolution 2D-electrophoresis, indicative of different compositional patterns of plasma and cerebrospinal fluids.

Colonic and gastric mucus-associated antigens: a comparative immunohistological study in precancerous and cancerous rat intestinal mucosa

Gastric M1 antigens were previously shown to be oncofetal markers for the colon in man and in the rat. They were observed very early during carcinogenesis in goblet cells of precancerous colonic mucosa; using an immunohistological method, we found that M1 were produced in 68% (41/60) of colonic adenocarcinomas and in 33% (21/63) of duodenal adenocarcinomas. M3C antigen has been described as being associated with human colonic mucus; in the rat it is restricted to the proximal colon. We found that M3C was produced in 91% (55/60) of colonic adenocarcinomas and in 15% (8/53) of duodenal adenocarcinomas. Before tumor appearance, M3C was sometimes expressed by goblet cells of the distal colon. We could not find it during fetal life. We have concluded that mucus-associated antigens can characterize modifications in cell differentiation in rat colonic carcinomas.