Maksimov Pavlo, Zerweck Johannes, Maksimov Aline, Hotop Andrea, Gross Uwe, Pleyer Uwe, Spekker Katrin, Däubener Walter, Werdermann Sandra, Niederstrasser Olaf, Petri Eckhardt, Mertens Marc, Ulrich Rainer G, Conraths Franz J, Schares Gereon
Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Wusterhausen, Germany.
Clin Vaccine Immunol. 2012 Jun;19(6):865-74. doi: 10.1128/CVI.00119-12. Epub 2012 Apr 11.
Toxoplasma gondii infections occur worldwide in humans and animals. In immunocompromised or prenatally infected humans, T. gondii can cause severe clinical symptoms. The identification of specific epitopes on T. gondii antigens is essential for the improvement and standardization of the serological diagnosis of toxoplasmosis. We selected 20 peptides mimicking linear epitopes on GRA1, GRA2, GRA4, and MIC3 antigenic T. gondii proteins in silico using the software ABCpred. A further 18 peptides representing previously published epitopes derived from GRA1, SAG1, NTPase1, and NTPase2 antigens were added to the panel. A peptide microarray assay was established to prove the diagnostic performance of the selected peptides with human serum samples. Seropositive human serum samples (n = 184) were collected from patients presenting with acute toxoplasmosis (n = 21), latent T. gondii infection (n = 53), and inactive ocular toxoplasmosis (n = 10) and from seropositive forest workers (n = 100). To adjust the cutoff values for each peptide, sera from seronegative forest workers (n = 75) and patients (n = 65) were used. Univariate logistic regression suggested the significant diagnostic potential of eight novel and two previously published peptides. A test based on these peptides had an overall diagnostic sensitivity of 69% (100% in ocular toxoplasmosis patients, 86% in acutely infected patients, 81% in latently infected patients, and 57% in seropositive forest workers). The analysis of seronegative sera performed with these peptides revealed a diagnostic specificity of 84%. The results of our study suggest that the use of a bioinformatic approach for epitope prediction in combination with peptide microarray testing is a powerful method for the selection of T. gondii epitopes as candidate antigens for serological diagnosis.
弓形虫感染在全球范围内的人类和动物中均有发生。在免疫功能低下或产前感染的人类中，弓形虫可引发严重的临床症状。鉴定弓形虫抗原上的特定表位对于改善和标准化弓形虫病的血清学诊断至关重要。我们使用ABCpred软件在计算机上选择了20种模拟弓形虫GRA1、GRA2、GRA4和MIC3抗原蛋白线性表位的肽段。另外，将代表先前发表的源自GRA1、SAG1、NTPase1和NTPase2抗原表位的18种肽段加入该组。建立了肽微阵列分析方法以验证所选肽段对人血清样本的诊断性能。从患有急性弓形虫病（n = 21）、潜伏性弓形虫感染（n = 53）和静止性眼弓形虫病（n = 10）的患者以及血清学阳性的林业工人（n = 100）中收集了血清学阳性的人血清样本。为调整每种肽段的临界值，使用了血清学阴性的林业工人（n = 75）和患者（n = 65）的血清。单因素逻辑回归表明8种新肽段和2种先前发表的肽段具有显著的诊断潜力。基于这些肽段的检测总体诊断敏感性为69%（眼弓形虫病患者中为100%，急性感染患者中为86%，潜伏感染患者中为81%，血清学阳性的林业工人中为57%）。用这些肽段对血清学阴性血清进行分析显示诊断特异性为84%。我们的研究结果表明，将生物信息学方法用于表位预测并结合肽微阵列检测是选择弓形虫表位作为血清学诊断候选抗原的有力方法。
