Abstract: 【Abstract】  Cystatins are reversibly tight-binding natural inhibitors of cysteine proteases. Cystatins in parasitic nematodes not only have the unique inhibition activity on cysteine proteases but also modulate the host immune response and have an important role in the immune evasion from host response and the adaptation to parasitism. This article reviews the classification, structure characteristics and function mechanism of cystatins, and the research progress on cystatins in parasitic nematodes.

Key words: Parasitic nematode, Cystatin, Immunomodulation