Histochemical and immunohistochemical study on GSA-II binding glycoprotein of alimentary tract

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(1) Mucous neck cells (MNCs) of the fundic gland are phylogenetically thought to have first appeared in amphibians. We studied the origin and differentiation of MNCs in fundic glands of xenopus laeves. By means of lectin histochemical methods using Griffonia simplicifolia agglutinin(GSA)-II, MNCs were detected specifically in fundic glands of adult X. laeves. During the morphogenetic period of the stomach in metamorphosing larvae, GSA-II reactive cells randomly appeared in various portions of the underdeveloped fundic glands and then rapidly localized in the neck portion. At this time, newly appearing mucous granules of MNC type were labeled by GSA-II-colloidal gold(CG). Two types of cells intermediate to MNCs and SMCs and intermediate to MNCs and OPCs were observed in the larval gastric region. Cellsintermediate to MNCs and OPCs were also found in adults. In these cells, mucous granules of MNC type were labeled by GSA-II-CG, but mucous granules of SMC type and zymogen-like granules di … More d not react to GSA-II. These observations suggest that GSA-II is a useful marker in studying the differentiation of MNCs and their precursors regardless of species differentiation.(2)We have examined cellular differentiation and migration in the fundic glands of adult X. laevis as well as its larvae using bromodeoxyuridine(BrdU)immunohistochemistry. In the adult fundic glands, cumulative labeling with BrdU revealed a proliferative cell zone between the SMCs and MNCS, in what is referred to as in the neck portion of the fundic gland. The labeling index of MNCs rapidly increased by week 5. The labeling index of OPCs showed the delayed-increase by week 7, coincident with the decrease in the labeling of MNCs. In the immature fundic glands of larvae, the labeled proliferating cells randomly distributed throughout the developing gastric mucosa. During the metamorphosing period, the labeling index of immature epithelial cells was the highest at stage 63. After the administration of BrdU to larvae at stage 63, there was no significant loss of the labeled epithelial cells during the metamorphosing period. Furthermore, there was no significant difference in the labeling indices among the epithelial cells such as SMCs/generative cells, MNCs, and OPCs at 7 days after administration. In adult gastric mucosa, generative cells might differentiate directly to SMCs in an upward direction. A majority of OPCs seemed to differentiate during a downward migration. Generative cells pass through a stage as MNCS, finally becoming OPCS. In histogenetic period of larval gastric region, undifferentiated cells might proliferate and differentiate to SMCS, MNCs and OPCs in situ. They may have migrated during stages 64 and 65. Histogenesis of adult gastric mucosa completed at stage 66.(3)We have purified GSA-II-binding glycoprotein from rat gastric mucosa. Before trying purification of this glycoprotein, we have established the assay system for GSA-II binding glycoprotein using the enzyme-linked lectin assay(ELLA)method. Glycoprotein from rat gastric mucosa was solubilized in the guanidineHCL buffer, then applied on to Sephacryl S-1000 column. The fraction containing GSA-II binding glycoprotein was applied to RCA-I-agarose column. The sample retained in RCA-I column was subsequently affinity-purified through GSA-IIagarose column. It is likely that purified GSA-II-binding glycoprotein allows to develop specific antibody and to shed light on this project. Less