The complement system is an important component of the innate immune system, which contributes to non-specific host defence. Particulate matters, such as invading pathogens and nanomedicines, in the blood may activate the complement system through classical, lectin and alternative pathways. Complement activation can aid recognition and clearance of particulate matters by immune cells, but uncontrolled complement activation can inflict damage and be life threatening. Plasma proteins on adsorption to surfaces of nanoparticles also play a significant role in complement activation and particularly through the alternative pathway. This process is continuous and changeable in vivo; protein-complement complexes are formed on the nanoparticle surface and then released and the cycle repeats on further plasma protein deposition. This complement activation turnover poses a challenge for design of immune-safe nanomedicines.

中文翻译：

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纳米粒子表面的补体活化周转

补体系统是先天免疫系统的重要组成部分，有助于非特异性宿主防御。血液中的微粒物质，如入侵的病原体和纳米药物，可以通过经典途径、凝集素和替代途径激活补体系统。补体激活可以帮助免疫细胞识别和清除颗粒物，但不受控制的补体激活会造成损害并危及生命。吸附到纳米颗粒表面的血浆蛋白也在补体激活中发挥重要作用，尤其是通过替代途径。这个过程在体内是连续的、多变的；蛋白质-补体复合物在纳米颗粒表面形成，然后释放，循环在进一步的血浆蛋白质沉积上重复。