Electrophoretical and Immunochemical Studies on Glycoproteins in Gastric Juice, Especially on the Components Related to Hakkinen's Fetal Sulphoglycoprotein Antigen

Electrophoretical and immunochemical analysis of glycoproteins (Gp) fractionated from gastric juice by Hakknine's cetyl pyridinium chloride precipitation method were carried out and the following results were obtained. 1) Patterns of cellulose acetate electrophoresis (CAEP) by alcian blue and coomasie blue staining were compared in a series of gastric juice Gp from various gastroduodenal diseases. CAEP patterns were classified into two main types, N and A types, according to the appearance of P-1 peak ; the N type had the P-1 but the A type did not. The latter type was subdivided into 3 types, A-1, A-2 and A-3. 2) The P-1 peak was stained by alcian blue but not by coomasie blue, and its mobility was slightly slower than chondroitin sulfate A. It was presumed that the occurrence of P-1 might be related to the normal secretory function of the stomach. In contrast, a P-1' peak observed in A-1 and A-3 types was positive both for alcian blue and protein staining and had a slower mobility than P-1 peak. This component probably had some relation to atrophy of gastric mucosa and low acid output. A similarity in the CAEP pattern between the A-3 type in Gp of gastric cancer and "polydispersed pattern" presented by Hakkinen was noticed. 3) Antisera against Gp of normal control (GpN), gastric ulcer (GpU), atrophic gastritis (GpA) and of gastric cancer (GpCa) were respectively raised in rabbits, and prior to use they were absorbed with normal human plasma and ABO red cells and antibody globulins were prepared. In immunoelectro-phoresis various Gp's showed complex patterns consisting of several precipitin lines from albumin to j3-globulin regions against various anti-Gp sera. Therefore, it was difficult to identify the precipitin lines and to correlate individual lines with features of gastric diseases. 4) After absorption of the antiserum against cancerous Gp (A-GpCa) with GpN, a precipitin arc having i3-mobility was detected for GpCa. This component was tentatively named Ca-Ag and the incidences by Ouchterlony method were 71% for gastric cancer, 51% for atrophic gastritis and 36% for gastric ulcer. The occurrence of this antigen was not coincided with that of either CEA or NCA in Gp's disease states. 5) By an indirect immunofluorescence technique, absorbed A-GpCa showed specific fluorescence on the inside of tubules of gastric adenocarcinoma and on the surface of cancer cells and, in part, on intratubular secretions and also on mucosa with intestinal metaplasia. No specific staining was obtained in normal gastric glands with the absorbed A-GpCa. This finding may mainly indicate the localization of Ca-Ag, suggesting a similarity with CEA or FSA. However, from the results of Ouchterlony's reactions it was considered that Ca-Ag would be a different cancer-related antigen than CEA or FSA, and that Ca-Ag was also related to atrophic changes of gastric mucosa