Which pattern recognition receptors are important in detecting oral biofilm components in epithelial cells?

• A. NOD-like receptors and G protein-coupled receptors contribute to detection.
• B. Toll-like receptors (TLRs) and NOD-like receptors contribute to detection.
• C. Nuclear receptors detect microbial components.
• D. Ion channels detect microbial components.

Answer: (B)

Pattern recognition receptors that detect oral biofilm components in epithelial cells are Toll-like receptors on the cell surface and in endosomes, together with NOD-like receptors in the cytoplasm. TLRs recognize extracellular and endosomal microbial molecules such as LPS, lipoproteins, peptidoglycan, and flagellin, triggering signaling pathways that lead to inflammatory cytokine production and antimicrobial peptide release. NLRs sense intracellular microbial fragments like peptidoglycan components and can form inflammasomes to drive maturation of IL-1β and IL-18, boosting the innate response. This combination allows epithelial cells in the mouth to rapidly detect biofilm bacteria and coordinate an effective defense. Nuclear receptors, ion channels, and GPCRs are not the primary pattern recognition receptors for detecting microbial PAMPs in this context.