The immunosuppressive functions of two novel tick serpins, HlSerpin‐a and HlSerpin‐b, from Haemaphysalis longicornis

• DOI: 10.1111/imm.13130
• Publication Date: 2019-10-13T11:39:38Z
• Authors: Fanqi Wang; Zhenyu Song; Jing Chen; Qihan Wu; Xia Zhou; Xiaohua Ni; Jianfeng Dai
• Keywords: Haemaphysalis longicornis

Serpins are evolutionarily conserved serine protease inhibitors that widely distributed in animals, plants and microbes. In this study, we reported the cloning functional characterizations of two novel serpin genes, HlSerpin-a HlSerpin-b, from hard tick Haemaphysalis longicornis China. Recombinant HlSerpin-b displayed inhibitory activities against multiple mammalian proteases. Similar to other serpins, suppressed expression inflammatory cytokines such as TNF-α, interleukin (IL)-6 IL-1β lipopolysaccharide-stimulated mouse bone-marrow-derived macrophages (BMDMs) or dendritic cells (BMDCs). The minimum active region (reaction centre loop) HlSerpin-a, named SA-RCL, showed similar biological inhibition immune suppression assays. immunosuppressive full-length SA-RCL impaired Cathepsin G B knockout macrophages, suggesting immunomodulation functions SA dependent on their activity. Finally, both HlSerpins can relieve joint swelling response collagen-induced arthritis models. These results suggested arthropod minimal reactive peptide is a potential candidate for drug development diseases.