Preparation of a Nanobody Specific to Dectin 1 and Its Anti-inflammatory Effects on Fungal Keratitis

Abstract

Xing Liu,1 Jianxin Sui,2 Cui Li,1 Xudong Peng,1 Qian Wang,1 Nan Jiang,1 Qiang Xu,1 Luokai Wang,2 Jing Lin,1 Guiqiu Zhao1 1Department of Ophthalmology, Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China; 2College of Food Science and Engineering, Ocean University of China, Qingdao, People’s Republic of ChinaCorrespondence: Jing Lin; Guiqiu ZhaoDepartment of Ophthalmology, Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, Shandong, People’s Republic of China, Email [email protected]; [email protected]: To prepare a nanobody specific to dectin 1 and verify its specificity and anti-inflammatory effects on Aspergillus fumigatus keratitis.Methods: The nanobody was selected from a high-quality shark-antibody library constructed with phage-display technology. The nanobody was developed in the expression systems of Escherichia coli. Indirect ELISA was used to determine the specificity of the nanobody to recombinant dectin 1 protein. The potential of the nanobody to be recognized and expressed on the surfaces of cells and corneas was detected by immunofluorescence, and its anti-inflammatory effect on A. fumigatus keratitis was further verified. After infection with A. fumigatus, eyes of C57B L/6 mice were treated with nanobodies. Human corneal epithelial cells (HCECs) were pretreated with nanobodies and then incubated with A. fumigatus. Clinical scores and slit-lamp photography were used to assess disease response in mouse corneas. RT-PCR and ELISA were used to evaluate mRNA and protein expression of IL1β and IL6 in both mouse corneas and HCECs.Results: The nanobody was successfully expressed through microbial system and showed specific high-affinity binding to recombinant dectin 1. Furthermore, it exhibited specific binding to dectin 1 expressed on the surfaces of cells and recognized dectin 1 in mouse corneas. Importantly, it reduced clinical scores of A. fumigatus keratitis in mice compared with a PBS-treatment group. In addition, it decreased mRNA and protein expression of IL1β and IL6 in infected corneas and HCECs stimulated with A. fumigatus.Conclusion: These results suggest that this nanobody can bring about anti-inflammatory effects. This highlights the potential of these nanobodies as innovative therapeutic agents in A. fumigatus.Keywords: nanobody, Aspergillus fumigatus, dectin 1, inflammation, cornea

Keywords

• nanobody
• aspergillus fumigatus
• dectin-1
• inflammation
• cornea