Stimulation of the absorption of macromolecules in Giardia lamblia infected mice intestine.

The absorption of 125I-labelled bovine serum albumin, gamma-globulin and alpha-lactalbumin was considerably enhanced in G. lamblia infected Swiss mice intestine compared to uninfected controls. The binding of 125I-proteins to brush border membrane was however, significantly (P less than 0.01) low in infected animals. Kinetic studies with gamma-globulin binding to brush borders revealed a decrease in the number of binding sites in infected animals (1.52) compared to controls (2.86 micrograms/mg protein) with no change in the affinity constant (47.60 micrograms/ml) under these conditions. These findings suggest that G. lamblia infection in mice leads to enhanced macromolecular absorption which seems unrelated to the binding of proteins to epithelial cell surface.