The SPIB gene is a marker for M cells and induced M cell expression will affect the ability of S. flexneri and other enteric pathogens to infect the epithelium.34,68,69 Coupled with the induced MUC2 results and the literature, our data indicate that the malnourished conditions altered cellular differentiation to varying degrees, which has implications for infection patterns of pathogens (see below). This evidence concerns the gene SPIB and infection.