Teichoic acids are polymeric building blocks of the cell wall of Gram-positive bacteria. They can make up 20-40% of their cell wall dry mass. Through esterification with lipids, lipoteichoic acids are formed, which also span the cell wall. The lipid moiety anchors the long molecule in the lipid layer of the cytoplasmic membrane.
Teichoic acid and lipoteichoic acids interact as PAMPs with certain receptors on inflammatory cells (e.g. macrophages/granulocytes), which leads via a cascade of intracellular signals to a release of cytokines with a febrile subsequent reaction. They thus represent exogenous pyrogens.