Journal of Pure and Applied MicrobiologyVol. 8 No. 2

Purified Suilysin Secreted by Streptococcus suis Serotype 2 Induce Interleukin-6 by Rat Brain Microvascular Endothelial Cells

Yang Guo1,2,3*, Pengfei Yi1*, Tao Zhang3, Xinyi Zhu4, Ge Hu3, Hong Dong3, Daixun Jiang3, Huiqin Duan3, Jianfang Wang3, Xiang Mu3* and Xubin Wei1*

1 College of Animal Science and Veterinary Medicine, Jilin University, Changchun Jilin130062, P. R. China. 2College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang Liaoning - 110 161, P. R. China. 3Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, Beijing University of Agriculture, Beijing 102206, P. R. China. 4 Archives of Northeast university, Shenyang Liaoning 110004, P. R. China.

Received on 09 January 2014 and accepted on 18 March 2014



Streptococcus suis (S. suis) serotype 2 is an important pathogen of pigs causing various diseases, including meningitis, and how the pathogen cross the blood-brain barrier (BBB) is unclear. As an important virulence factor of S. suis, suilysin is shown to be helpful for the S. suis crossing the BBB. The aim of this study was to investigate the ability of suilysin produced by S. suis serotype 2 strain CVCC606 to induce the release of pro-inflammatory cytokine by rat brain microvascular endothelial cells (RBMVECs), first suilysin was purified by using different filtration steps, fractional precipitation with ammonium sulfate and Sephadex G-100 column chromatography. Then RBMVECs were exposed to suilysin, intracellular lactate dehydrogenase (LDH) and interleukin (IL)-6 release assays were employed, a time- and dose-dependent cytotoxicity of suilysin to RBMVECs was observed, and high levels of IL-6 production by RBMVECs could be induced with suilysin. Our findings suggest that cell injury and pro-inflammatory cytokine release of RBMVECs induced with suilysin is contribute to increase BBB permeability, and suilysin may be involved in the pathogenesis of meningitis caused by S. suis.

Keywords : Suilysin; Streptococcus suis; purification; cell injury; cytokine; Microvascular endothelial cells