C4b-binding protein (C4BP) によるTLR応答制御機構  [in Japanese] TLR-regulatory system of C4b-binding protein (C4BP)  [in Japanese]

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<p> Complement system, one of the innate immunities, is a strong immune system, which destroys invasive microbes by making a hole in the cell membranes. On the other hands, several proteins inhibit complement system to protect the host cells from the attack. C4b-binding protein (C4BP), one of the inhibitory proteins, constitutively exists at high density called 200 μg/mL in serum. C4BP binds to C4b or C3b and helps the degradation, followed by prevention against the activation of complement system.</p><p> Recently, we found that C4BP associates with Toll-like Receptor (TLR) 2, one of the pathogen recognition receptors (PRRs), and regulates the activation response through TLR2. Furthermore, we found that C4BP also binds to TLR4, which was other PRR, and regulates the activation response through TLR4. A competition assay by using two kinds of anti-TLR4 mAb revealed that C4BP prevents an interaction between TLR4/MD-2 and its ligand. These findings indicate that C4BP binds to TLRs on the cell surface and inhibits the interaction between TLRs and the ligands, followed by inhibition of TLR activation.</p><p> Here we explain the function of C4BP to affect complement and TLR, which is called the two major immune systems. We also give an outline about a unique other function of C4BP and influence on disease onset.</p>


  • Endotoxin and Innate Immunity

    Endotoxin and Innate Immunity 21(0), 47-50, 2018

    Japanese Endotoxin and Innate Immunity Society



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