Innate Immunity Activation Antibody Sampler Kit

Background

The innate immune system responds rapidly to pathogens by detecting conserved pathogen-associated molecular patterns (PAMPs) and damage/danger-associated molecular patterns (DAMPs) through pattern recognition receptors (PRRs). There are several families of PRRs. Toll-like receptors (TLRs) are transmembrane PRRs and signal through recruitment of adaptor proteins, including MyD88, which leads to recruitment and phosphorylation of IRAK1 and IRAK4, followed by activation of NF-κB and MAP kinases (1-3). Some TLRs also activate IRFs, which upregulate the type I interferon response. Activation of TLR3 and TLR4 results in phosphorylation and activation of IRF-3, while TLR7, TLR8, and TLR9 lead to activation of IRF-7 (2, 3). STING is a multi-pass ER transmembrane protein that is activated in response to intracellular DNA downstream of DNA-sensing cytoplasmic PRRs, such as DDX41, or by binding the second messenger cyclic-GMP-AMP (cGAMP) produced by cGAS (4-6). Following activation, STING translocates with TBK1 to perinuclear endosomes, leading to phosphorylation and activation of IRF-3 and NF-κB (7, 8). Following activation and translocation, STING gets phosphorylated by ULK1, resulting in STING inactivation and degradation (9). Inflammasomes are cytoplasmic multimeric protein complexes that assemble in response to PAMPs or DAMPs detected by AIM2 or members of the nod-like receptor (NLR) family, such as NLRP3 (10). Inflammasomes activate Caspase-1, which cleaves the IL-1β and IL-18 precursor proteins into the mature forms (10).