Development of a primary mouse intestinal epithelial cell monolayer culture system to evaluate factors that modulate IgA transcytosis

There is significant interest in the use of primary intestinal epithelial cells in monolayer culture to model intestinal biology. However, it has proven to be challenging to create functional, differentiated monolayers using current culture methods, likely due to the difficulty in expanding these cells. Here, we adapted our recently developed method for the culture of intestinal epithelial spheroids to establish primary epithelial cell monolayers from the colon of multiple genetic mouse strains. These monolayers contained differentiated epithelial cells that displayed robust transepithelial electrical resistance. We then functionally tested them by examining immunoglobulin A (IgA) transcytosis across Transwells. IgA transcytosis required induction of polymeric Ig receptor (pIgR) expression, which could be stimulated by a combination of lipopolysaccharide and inhibition of c-secretase. In agreement with previous studies using immortalized cell lines, we found that tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-17, and heat-killed microbes also stimulated pIgR expression and IgA transcytosis. Weused wild-type and knockout cells to establish that among these cytokines, IL-17 was the most potent inducer of pIgR expression/IgA transcytosis. Interferon-gamma, however, did not induce pIgR expression, and instead led to cell death. This new method will allow the use of primary cells for studies of intestinal physiology.