Function
Inhibitor of cysteine proteinases. Inhibits host immune responses, probably via its inhibition of host cathepsins. Contributes to the suppression of the host's immune response to tick salivary proteins and is important for successful feeding on hosts (PubMed:17698852). Down-regulates TLR2-mediated host responses to infection by B.burgdorferi and the production of chemokines CCL3 and CXCL10 by host dendritic cells (PubMed:25975355). Enhances infection by the tick-transmitted pathogen B.burgdorferi (in vitro) (PubMed:20545851). Inhibits host inflammatory responses to A.phagocytophilum infection (PubMed:24686067). Inhibits papain (in vitro) (PubMed:20545851). Inhibits cathepsin-L (CTSL) (in vitro) (PubMed:17698852, PubMed:20545851). Inhibits cathepsin-L2 (CTSV) (in vitro) (PubMed:17698852).