表皮葡萄球菌YycG单克隆抗体抗生物膜活性的研究

Effect of anti-YycG monoclonal antibody against Staphylococcus epidermidis biofilm formation

YycFG双组分信号转导系统调控葡萄球菌细胞壁合成、代谢及生物膜形成,PAS是组氨酸激酶YycG的胞外信号感应区域。本研究针对胞外PAS区域制备抗YycG-PAS单克隆抗体(YycG-PAS MAb)。免疫鉴定结果表明,YycG-PAS MAb可与重组YycG-PAS蛋白和表皮葡萄球菌菌体YycG蛋白结合,属于IgG2a亚型,效价为log 215。YycG-PAS MAb(80μg/ml)与表皮葡萄球菌RP62A菌株共培养24h,对细菌生物膜形成的抑制率达46.5%,与mIgG(80μg/mL)组相比有显著差异(P<0.05)。YycG-PAS MAb(80μg/ml)与低浓度万古霉素(1μg/ml)联用可增强对24h细菌生物膜的抑制作用,抑制率由57.6%提高至93.0%(P<0.01)。YycG-PAS MAb对浮游状态表皮葡萄球菌的生长及存活无显著影响。本研究为YycGPAS MAb在抗生物膜感染中的潜在应用价值奠定了一定基础。

Bacterial YycFG two‐component signal transduction system plays a major role in controlling cell wall synthesis , metabolism and biofilm formation of Staphylococcus . The extracellular PAS domain of YycG histidine kinase can sense various environmental signals .Therefore ,a monoclonal antibody targeting PAS domain of Staphylococcus epidermidis （S . epidermidis） was produced （YycG‐PAS MAb） .Enzyme‐linked immunosorbent assay （ELISA ） indicated that YycG‐PAS MAb belonged to IgG2a subclass and antibody titer was log 215 .Western blotting suggested that YycG‐PAS MAb had the ability to bind both recombinant YycG‐PAS protein and protein extracted from cells .Further investigation exhibited inhibitory effect of YycG‐PAS MAb （80 μg/ml） against biofilm formation after co‐incubation with S . epidermidis and the inhibitory rate was 46 .5% . The anti‐biofilm activity of YycG‐PAS MAb was improved when combined with low‐concentration of vancomycin （1 μg/ml） .The inhibitory rate was increased from 57 .6% 〈br〉 to 93 .0% （ P〈 0 .01 ） . No significant effects of YycG‐PAS MAb on viability and growth of planktonic bacterial cells were observed .This study indicated that YycG‐PAS MAb is a promising candidate antibody for biofilm‐related infections .