Toll-like receptors (TLRs) have been shown to play a pivotal role in both innate and acquired
immune responses. TLRs recognize various pathogen-associated molecular patterns (PAMPs) such as
bacterial lipopolysaccharide (LPS), viral RNA, CpG-containing DNA, and flagellin, among others. Their
activation and signaling lead to the induction of inflammatory cytokines and type I interferons for host
defense. In addition, the responses of the innate immune system are important not only in the elimination of
pathogens but also in the development of antigen-specific acquired immunity mediated by B and T cells.
TLRs are also involved in non-infectious diseases such as lung injury, COPD, fibrosis, allergy,
autoimmunity, and cancer. Here we describe some features of the regulation of TLRs in a variety of lung
diseases.
Keywords: TLRs, exogenous and endogenous ligands, signaling, innate and acquired, immunity lung disease.
