Wittek Natalia, Majewska Ewa
Zakład Patofizjologii i Immunopatologii Wysiłku.
Przegl Lek. 2010;67(7):484-7.
Cystatin C is a lowmolecular protein (13 kDa) that inhibits the activity of lysosomal cysteine proteinases with the strongest activity against cathepsin B and H. The recent experiments show that the level of cystatin C is independented of chronic and acute inflammatory process which frequently coexist with end stage renal diseases. Recent studies challange the theory because a higher concentration of cystatin C in serum correlated well with a higher concentration of inflammatory markers such as a CRP and fibrinogen in the patients. In vitro experiments on cultured monocytes and macrophages discovered that after stimulation by LPS and INF the expression of the cystatin C gene and synthesis of this protein was reduced. Cystatin C plays important modulatory function in regulation of the natural immunity, protecting our body against viruses, bacteries and parasites. Moreover, cystatin C binds the C4 component and modulates activation of the classical complement pathway. The experiments also show that cystatin C could influence non-specific immune response through the inhibition of the superoxide anion generation (respiratory burst), phagocytosis, chemotaxis and apoptosis of neutrophils. Similarly, the cystatin C can modulate the specific immune response through the inhibition of cathepsin S, bindining membrane receptors for TGF-beta or increasing MHC class II expression on dendritic cells.
胱抑素C是一种低分子蛋白质（13 kDa），可抑制溶酶体半胱氨酸蛋白酶的活性，对组织蛋白酶B和H的活性最强。最近的实验表明，胱抑素C的水平与终末期肾病常伴随的慢性和急性炎症过程无关。最近的研究对该理论提出了挑战，因为患者血清中较高浓度的胱抑素C与较高浓度的炎症标志物如CRP和纤维蛋白原密切相关。在培养的单核细胞和巨噬细胞上进行的体外实验发现，经脂多糖和干扰素刺激后，胱抑素C基因的表达和该蛋白的合成减少。胱抑素C在天然免疫调节中发挥重要的调节功能，保护我们的身体免受病毒、细菌和寄生虫的侵害。此外，胱抑素C结合C4成分并调节经典补体途径的激活。实验还表明，胱抑素C可通过抑制超氧阴离子生成（呼吸爆发）、吞噬作用、趋化作用和中性粒细胞凋亡来影响非特异性免疫反应。同样，胱抑素C可通过抑制组织蛋白酶S、结合转化生长因子-β的膜受体或增加树突状细胞上的MHC II类表达来调节特异性免疫反应。
