The Effect of Lectins on Crypt Cell Proliferation in Organ Culture

Lectins are highly active biological molecules that are present in large quantities in the human diet. Changes in colonic epithelial glycoconjugates, such as the enhanced expression of the Thomsen-Friedenreich (TF) antigen, are commonly seen in hyperplastic, premalignant, and malignant colorectal epithelium (1 ,2 ). As lectins, such as peanut agglutinin would be expected to bind to TF expressed on the epithelial cell (3 ), it is possible to hypothesize that this interaction could have profound biological effects. This hypothesis has been confirmed by the finding that PNA stimulates proliferation in colonic cancer cell lines (4 ) and in colonic explants from both normal (4 ) and diseased colonic epithelium (5 ). These findings suggest that many lectins may have effects on growth and oncogenesis in the colon; there is therefore a need for laboratory techniques to quantitate changes in proliferation in the human colonic epithelium.