Furthermore, these mice also display loss of MMP-7, a protease that is important for activation of the defensin family of proteins, and thus also serves as a Paneth cell marker.43 Various studies have indicated that another class of defensins namely, the β-defensins – secreted by enterocytes in both the large and the small intestines constitutively and in response to infection – play a critical role in the colon. Here, MMP7 is linked to infection.