Differential activation of the Toll-like receptor 2/6 complex by lipoproteins of Streptococcus suis serotypes 2 and 9

作者：Schreur Paul J Wichgers^*; Rebel Johanna M J; Smits Mari A; van Putten Jos P M; Smith Hilde E

来源：Veterinary Microbiology, 2010, 143(2-4): 363-370.

DOI：10.1016/j.vetmic.2009.12.010

• Streptococcus suis
• TLR activation
• Lipoproteins

Streptococcus suis causes invasive infections in pigs and occasionally in humans. Worldwide, S. suis serotype 2 is most frequently isolated from diseased piglets, but the less virulent serotype 9 is emerging, at least in Europe. We compared the activation of human Toll-like receptors (hTLRs) by S. suis serotype 2 and 9 strains to better understand the role of the innate immune response in fighting S. suis infections. Neither live nor heat-killed log phase grown S. suis activated the hTLR1/2, hTLR2/6 and hTLR4/MD-2 complexes. However, the hTLR2/6 complex was specifically activated by both serotypes after disruption of the cell wall synthesis using penicillin. Activation levels of the hTLR2/6 complex were higher for serotype 9 strains compared to serotype 2 strains suggesting intrinsic differences in cell wall composition between both serotypes. The hTLR2/6 activating fractions decreased in molecular size after digestion with proteinase K and were sensitive for lipoprotein lipase digestion and NaOH hydrolysis, indicating lipoprotein(s) as active component(s). Overall, our results indicate that S. suis lipoproteins activate TLR2/6 but not TLR1/2 and that the clinically different serotypes 2 and 9 display differential release of TLR ligand when cell wall integrity is compromised.

• 出版日期2010-7-14