The inner of the two Muc2 mucin-dependent mucus layers in colon is devoid of bacteria.

We have recently shown that the colon is protected by an inner mucus layer that efficiently separates the bacteria in the outer mucus from the epithelial cells. The inner mucus is impervious for bacteria and built by a network formed by the MUC2 mucin. Lack or defects in this inner mucus layer allow bacteria to reach the epithelia, something that triggers colon inflammation.