[Recombinant porcine lung surfactant protein A inhibits porcine reproductive and respiratory syndrome virus infection into host cells in vitro].
OBJECTIVE
To investigate the antiviral activity of porcine lung surfactant protein A (SP-A) to porcine reproductive and respiratory syndrome virus (PRRSV) in vitro.


METHODS
The SP-A gene was amplified by PCR from the plasmid containing porcine SP-A gene, and subcloned into pcDNA3. 1A-CD5 vector containing the human CD5 signal peptide to generate SP-A eukaryotic expression vector pcDNA-CD5-SPA/MH. The recombinant expression vector was transfected into HEK293T cells mediated with calcium phosphate. The expressed recombinant SP-A was identified by Western blot and purified from culture medium by Ni-NTA-Agarose beads. The binding activity of SP-A with PRRSV was identified by ELISA. The antiviral activity of SP-A to PRRSV was analyzed by viral titer reduction assays on MARC-145 cells and porcine alveolar macrophages (PAM).


RESULTS
The results showed that the eukaryotic expression vector of SP-A gene could mediate SP-A expression in HEK293T cells, the expressed SP-A could bind PRRSV in a dose dependent manner. The PRRSV incubated in advance with SP-A showed the lower infective activity compared with no-SP-A-incubated PRRSV on both MARC-145 cells and porcine alveolar macrophages. The SP-A-treated PRRSV titers in MARC-145 cells and PAM cells were significantly lower than that of SP-A-untreated PRRSV at 72 h post-infection.


CONCLUSIONS
Recombinant porcine SP-A significantly inhibit the infection of PRRSV to the host cells in vitro, which indicates that recombinant SP-A possesses anti-PRRSV activity.
Department of Basic Veterinary Medicine, College of Veterinary Medicine, Agricultural University of Hebei, North China Research Center of Animal Epidemic Pathogen Biology, Ministry of Agriculture of China, Baoding 071001, China. zhangfeng2084@163.com
Feng
F
Zhang
Fei
F
Zhong
Xiujin
X
Li
Xingxing
X
Wang
Kao
K
Zhang
Huihui
H
Chen
Zhen
Z
Li
Wenyan
W
Li
Hongli
H
Pan
Dongmei
D
Han
D000818:Animals; D002460:Cell Line; D057809:HEK293 Cells; D006801:Humans; D016676:Macrophages, Alveolar / Q000276:immunology / Q000821:virology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology / Q000502:physiology*; D037662:Pulmonary Surfactant-Associated Protein A / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D013552:Swine; D014779:Virus Replication
D037662:Pulmonary Surfactant-Associated Protein A; D011994:Recombinant Proteins