preview

The Innate Immune System

Decent Essays
Open Document

In the initial phase of an infection, the innate immune system generates a rapid inflammatory response that blocks the growth and dissemination of the infectious agent. This response is followed, in vertebrates, by the development of an acquired immune response in which highly specific B and T cell receptors recognize the pathogen and induce responses that lead to its elimination (Janeway, Jr. et al., 2002). The antigen receptors of the acquired immune system are well characterized. They consist of many structurally similar molecules with different binding specificities created by somatic rearrangements and mutations within the binding site regions of the B and T cell receptor variable domains (Jung et al., 2004;Schatz et al., 2005). By contrast, the receptors of the innate immune …show more content…

All ECDs assume the typical horseshoe-shape, but their structures cannot be superimposed because of variations in curvature. In the known structures, the glycans are
Botos et al. Page 3
Structure. Author manuscript; available in PMC 2012 April 13.
NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript distributed throughout the molecule, except for the lateral face formed by the ascending loops of the LRRs (Figure 2). This glycan-free face is involved in dimerization upon ligand binding in the known TLR/ligand structures (see below).
The TLR1/2/6/10 subfamily
TLR2 resides on the plasma membrane where it responds to lipid-containing PAMPs such as lipoteichoic acid and di- and tri-acylated cysteine-containing lipopeptides (Takeda et al.,
2003). It does this by forming dimeric complexes with either TLR1 or TLR6 on the plasma membrane. The structures of TLR2/TLR1 and TLR2/TLR6 with lipopeptide ligands have been determined (Jin et al., 2007;Kang et al., 2009). To facilitate crystallization and structure determination the LRR-CT and the last one or two LRRs of TLRs 1, 2, and 6

Get Access