Figure 2.

Sensing and controlling the microbiota. (A) The appropriate detection and antigen sampling of the microbiota through many mechanisms results in a healthy host response leading to control of the microbiota. (B) Defective detection of the microbiota and an insufficient host response leads to a loss of control of the microbiota, including the expansion of the total bacteria or specific bacterial populations. DC, dendritic cell; MAMP, microbe associated molecular pattern; IgA, immunoglobulin A; TLR, toll-like receptor; NOD, nucleotide-binding oligomerization domain.