Fig. 1.

Microbial components such as lipopolysaccharides (LPS), lipoteichoic acid (LTA), formylated peptides, and flagellin serve as microbial-associated molecular patterns (MAMPs) and signal pattern recognition receptors (PRRs) including Toll-like receptors (TLRs), formylated peptide receptors (FPRs), or nucleotide-binding oligomerization domain-like receptors (NODs). Integration of these signals evokes cellular outputs based on the initial perception of the triggering organism. Output can be a protective response to commensal microbiota, an inflammatory response to pathogenic organism(s), or it can trigger apoptosis (reproduced with permission from Sharma et al. [12])