Direct effects of wheat germ agglutinin on inositol phosphate formation and cytosolic-free calcium level in intestine 407 cells.

The interaction between dietary lectins, especially wheat germ agglutinin (WGA), and intestinal cells has been implicated in the pathogenesis of celiac disease. The present study was undertaken to investigate the immediate effects following such an interaction. Direct WGA-stimulation of Intestine 407 cells leads to an immediate rise in the cytosolic-free calcium concentration. The major part of this lectin-induced rise is due to an influx of calcium across the plasma membrane into the cytosol. However, WGA-exposure also results in an immediate mobilization of calcium from intracellular stores, most likely mediated via the simultaneous increase of inositol trisphosphate formation in these cells. The transduction mechanism described for WGA in these intestinal cells is not very sensitive towards pertussis toxin, indicating that if a G-protein is involved, it differs from those of most other systems. The suggested role for WGA in changing the functional and structural properties of intestinal cells might involve increases of inositol phosphate and cytosolic-free calcium levels.