A novel nanobody specific for respiratory surfactant protein A has potential for lung targeting.
Lung-targeting drugs are thought to be potential therapies of refractory lung diseases by maximizing local drug concentrations in the lung to avoid systemic circulation. However, a major limitation in developing lung-targeted drugs is the acquirement of lung-specific ligands. Pulmonary surfactant protein A (SPA) is predominantly synthesized by type II alveolar epithelial cells, and may serve as a potential lung-targeting ligand. Here, we generated recombinant rat pulmonary SPA (rSPA) as an antigen and immunized an alpaca to produce two nanobodies (the smallest naturally occurring antibodies) specific for rSPA, designated Nb6 and Nb17. To assess these nanobodies' potential for lung targeting, we evaluated their specificity to lung tissue and toxicity in mice. Using immunohistochemistry, we demonstrated that these anti-rSPA nanobodies selectively bound to rat lungs with high affinity. Furthermore, we intravenously injected fluorescein isothiocyanate-Nb17 in nude mice and observed its preferential accumulation in the lung to other tissues, suggesting high affinity of the nanobody for the lung. Studying acute and chronic toxicity of Nb17 revealed its safety in rats without causing apparent histological alterations. Collectively, we have generated and characterized lung-specific nanobodies, which may be applicable for lung drug delivery.
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Shan-Mei
SM
Wang
School of Medicine, Suzhou University, SuZhou, People's Republic of China.
Xian
X
He
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Nan
N
Li
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Tongji University, Shanghai, People's Republic of China.
Feng
F
Yu
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Yang
Y
Hu
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Liu-Sheng
LS
Wang
Department of Chest Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Peng
P
Zhang
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Yu-Kui
YK
Du
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Shan-Shan
SS
Du
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Zhao-Fang
ZF
Yin
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Ya-Ru
YR
Wei
CSIRO (Commonwealth Scientific and Industrial Research) Materials Science and Engineering, Clayton.
Xavier
X
Mulet
CSIRO Materials Science and Engineering, Parkville, Melbourne, VIC, Australia.
Greg
G
Coia
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Dong
D
Weng
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Tongji University, Shanghai, People's Republic of China.
Jian-Hua
JH
He
Department of Basic Sciences, University of North Dakota, Grand Forks, ND, USA.
Min
M
Wu
Department of Respiratory Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Hui-Ping
HP
Li
D000818:Animals; D016503:Drug Delivery Systems; D051379:Mice; D008819:Mice, Nude; D037662:Pulmonary Surfactant-Associated Protein A / Q000276:immunology*; D051381:Rats; D061905:Single-Domain Antibodies / Q000737:chemistry / Q000276:immunology / Q000633:toxicity
D037662:Pulmonary Surfactant-Associated Protein A; D061905:Single-Domain Antibodies
VHH; lung-targeting drugs; nanobodies; phage-nanobody library; rSPA