Toll-like receptors (TLRs) are type I transmembrane signaling receptors characterized by containing leucine-rich repeats (LRR) extracellular domain and IL-1 receptor like intracellular domain. TLRs are responsible for recognizing pathogen-associated molecule patterns (PAMPs). They are primary sensors of both innate and adaptive immune systems. To date a total of 12 TLRs have been indentified. Toll-like receptor 1 (TLR1), known as CD281, is expressed on monocytes/macrophages, dendritic cells, and granulocytes and some lymphocytes at low levels. By association with TLR2, TLR1 is a coreceptor involved in the response to diverse set of pathogens, such as triacylated lipopeptidess (but not diacylated lipopeptides), peptidoglycans, lipoteichoic acid.