Isolation of a putative cell adhesion mediating lectin from teratocarcinoma stem cells and its possible role in differentiation.

We have identified a cell surface teratocarcinoma stem cell lectin with a fucan/mannan specificity by the use of an erythrocyte rosetting assay as well as hemagglutination assay. We have also described experiments that suggest that the lectin is involved in mediating divalent cation-independent adhesion of the stem cells. This molecule has been purified from stem cell conditioned medium and identified as a polypeptide of 56 000 apparent molecular weight. An antibody has been raised to this 56K polypeptide (using material eluted from an SDS-polyacrylamide gel as the immunogen) and its specificity determined by protein blot analysis. In addition, we have recently observed that only carbohydrates recognized by the lectin interfere with in vitro embryoid body formation by the stem cells, suggesting that the lectin may be involved in differentiation.