Characterization of the mucins produced by normal human colonocytes in primary culture

Mature goblet cells filled with mucin ready for secretion represent about one third of the cells in primary cultures of human colonocytes. In the present study characterization of the mucins produced by cultured human colonocytes was made by histochemical methods by lectin and monoclonal antibody binding. Two monoclonal antibodies and three lectins (Dolichos biflorus (DBA), Helix pomatia (HPA) and Arachis hypogea (PNA) recognizing epitopes or sugar haptens characteristic of different stages of mucin glycoprotein maturation, were employed. The reactivity to these probes was tested both on cultured colonocytes and on tissue sections of the normal colon mucosa. The results show that the mucins produced in culture are glycosylated to the mature form, as they show the same reactivity to lectins and antibodies of the mucins expressed in tissue sections of the normal colon mucosa. In addition, it is demonstrated that cultured human colonocytes do not express mucins reactive to PNA, which are characteristic of tumors. Since the cultured colonocytes maintain the expression of differentiated functions for at least three days, they may offer a useful model to study metabolism, function and regulation of colon mucins in health and disease.