Regional Medical Research Centre (Indian Council of Medical Research), WHO Collaborating Centre for Diagnosis, Reference, Research and Training in Leptospirosis, Port Blair-744103, Andaman and Nicobar Islands, India.
Mol Biol Rep. 2019 Jun;46(3):2799-2807. doi: 10.1007/s11033-019-04726-6. Epub 2019 Mar 8.
Identification and characterisation of novel antigenic proteins of Leptospira are necessary to unravel the secrets of the Leptospiral disease biology. Besides, the current scenario of Leptospirosis demands the development of advanced diagnostics with the potential of an early and specific diagnosis. This work reports the diagnostic efficacy of a PI-PLC (LA_1375) of Leptospira interrogans serovar Lai strain 56601. Phospholipases are enzymes that catalyse the degradation of membrane phospholipids, with the after effects of pathophysiological consequences through the impairment of cellular signalling mechanisms. The immunoblotting analysis allows to identify the Leptospirosis positive serum samples demonstrated the expression and exposure of the protein to the immune system and confirmed the antigenic nature of the protein. Furthermore, evaluation of diagnostic efficacy of an ELISA to detect antibodies against recombinant PI-PLC has tested in indirect IgM ELISA using the purified 50 kDa recombinant protein as the coating antigen. A cut-off value of 0.218 at mean + 2SD and a sensitivity value of 100% and a specificity value of 95.65% explored for the rPI-PLC IgM ELISA. The PPV and NPV of ELISA for the Leptospirosis confirmed acute phase samples were 95.87% and 100% respectively. Comparison of the ELISA assay with MAT for the detection of Leptospiral antibodies showed a positive correlation (r value 0.345, p < 0.05), and signified the diagnostic efficacy of rPI-PLC for the definitive diagnosis of the Leptospirosis. In addition, the revealed conservation nature of PI-PLC among different Leptospira species highlights the diagnostic and vaccine candidate potential. Thus, the study emphasises the Leptospiral PI-PLC as a potential antigen still the importance as a novel biomarker candidate for the serodiagnosis and pathogenesis of Leptospirosis have to be investigated.
鉴定和描述钩端螺旋体的新型抗原蛋白对于揭示钩端螺旋体病生物学的秘密是必要的。此外，当前的钩端螺旋体病形势需要开发具有早期和特异性诊断潜力的先进诊断方法。本工作报告了来自问号钩端螺旋体血清型赖特 56601 菌株的磷脂酶 PI-PLC（LA_1375）的诊断功效。磷脂酶是一种催化膜磷脂降解的酶，通过损害细胞信号转导机制，产生病理生理后果。免疫印迹分析可识别出钩端螺旋体病阳性血清样本，表明该蛋白表达并暴露于免疫系统，证实了该蛋白的抗原性。此外，使用纯化的 50 kDa 重组蛋白作为包被抗原，在间接 IgM ELISA 中评估针对重组 PI-PLC 的 ELISA 检测抗体的诊断功效。在均值+2SD 处设定的截断值为 0.218，rPI-PLC IgM ELISA 的灵敏度值为 100%，特异性值为 95.65%。对于急性相样本，ELISA 的阳性预测值和阴性预测值分别为 95.87%和 100%。ELISA 检测与 MAT 检测钩端螺旋体抗体的比较显示出正相关（r 值为 0.345，p<0.05），表明 rPI-PLC 对钩端螺旋体病的诊断功效。此外，PI-PLC 在不同钩端螺旋体种属之间的保守性表明其具有诊断和疫苗候选潜力。因此，该研究强调了钩端螺旋体 PI-PLC 作为一种潜在的抗原，同时作为一种新的生物标志物候选物，对于钩端螺旋体病的血清学诊断和发病机制仍有待进一步研究。
