Concluding remarks
Metchnikoff was aware that the innate immune system evolved to efficiently detect essentially all pathogens. Later it became apparent that it does so with a remarkable economy of genes. The TLRs do so by detecting conserved pathogen-derived molecules, triggering both an innate and an adaptive immune response. The relatively loose specificity of the receptors is at least partly explained by cooperation between TLRs and scavenger receptor molecules such as CD14 and CD36, which also enhance the sensitivity of detection. In addition, these co-receptors may help to enforce the cell specificity of the innate response. Moreover, it must not be forgotten that the host has evolved numerous TLR-independent pathways that contribute to the eradication of pathogens, usually acting in concert with the TLR system. Together these pathways perform the almost impossible task of resisting infection by a nearly limitless variety of pathogens.
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Hoebe, K., Beutler, B. (2006). TLRs as bacterial sensors. In: O’Neill, L.A., Brint, E. (eds) Toll-like Receptors in Inflammation. Progress in Inflammation Research. Birkhäuser Basel. https://doi.org/10.1007/3-7643-7441-1_1
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