Polarized monolayer cultures of human intestinal epithelial cell lines exposed to intractable proteins - In vitro hazard identification studies

• Intractable proteins did not produce adverse effects toward human intestinal epithelial cell (IEC) monolayers. • Intractable proteins do not appear to be inherently hazardous as a class of proteins. • In vitro methods of protein hazard identification require much less protein than studies with laboratory animals. • Inexpensive and readily available cells, reagents, and instruments can be used for protein hazard identification.