Garcia João Luis, Navarro Italmar Teodorico, Vidotto Odilon, Gennari Solange Maria, Machado Rosângela Zacarias, da Luz Pereira Ademir Benedito, Sinhorini Idercio Luiz
Microbiology and Immunology Laboratory, Departamento de Biologia, Universidade Estadual do Centro Oeste-UNICENTRO, R. Simeão Camargo Varela de Sá, Bairro Cascavel, Guarapuava, PR, Brazil.
Exp Parasitol. 2006 Jun;113(2):100-5. doi: 10.1016/j.exppara.2005.12.011. Epub 2006 Feb 3.
Indirect ELISA and IFAT have been reported to be more sensitive and specific than agglutination tests. However, MAT is cheaper, easier than the others and does not need special equipment. The purpose of this study was to compare an enzyme linked immunosorbent assay using crude rhoptries of Toxoplasma gondii as coating wells (r-ELISA) with indirect fluorescence antibody test (IFAT) and modified agglutination test (MAT) to detect anti-T. gondii antibodies in sera of experimentally infected pigs. Ten mixed breed pigs between 6.5 and 7.5 weeks old were used. All pigs were negative for the presence of T. gondii antibodies by IFAT (titre < 16), r-ELISA (OD < 0.295) and MAT (titre < 16). Animals received 7x10(7) viable tachyzoites of the RH strain by intramuscular (IM) route at day 0. Serum samples were collected at days -6, 0, 7, 14, 21, 28, 35, 42, 50, and 57. IFAT detected anti-T. gondii antibodies earlier than r-ELISA and MAT. The average of antibody levels was higher at day 35 in IFAT (Log10=2.9) and in MAT (Log10 = 3.5), and at day 42 in r-ELISA (OD = 0.797). The antibody levels remained high through the 57th day after inoculation in MAT, and there was a decrease tendency in r-ELISA and IFAT. IFAT was used as "gold standard" and r-ELISA demonstrated a higher prevalence (73.3%), sensitivity (94.3%), negative predictive value (83.3%), and accuracy (95.6%) than MAT. Kappa agreements among tests were calculated, and the best results were shown by r-ELISAxIFAT (kappa = 0.88, p < 0.001). Cross-reaction with Sarcocystis miescheriana was investigated in r-ELISA and OD mean was 0.163 +/- 0.035 (n = 65). Additionally, none of the animals inoculated with Sarcocystis reacted positively in r-ELISA. Our results indicate that r-ELISA could be a good method for serological detection of T. gondii infection in pigs.
据报道，间接酶联免疫吸附测定法（ELISA）和间接荧光抗体试验（IFAT）比凝集试验更敏感、更具特异性。然而，改良凝集试验（MAT）成本更低，比其他方法更简便，且不需要特殊设备。本研究的目的是比较以粗制刚地弓形虫棒状体作为包被孔的酶联免疫吸附测定法（r-ELISA）与间接荧光抗体试验（IFAT）和改良凝集试验（MAT），以检测实验感染猪血清中的抗弓形虫抗体。选用了10头6.5至7.5周龄的杂种猪。通过IFAT（滴度<16）、r-ELISA（OD<0.295）和MAT（滴度<16）检测，所有猪的弓形虫抗体均为阴性。在第0天，动物通过肌肉注射（IM）途径接种7×10⁷个RH株活速殖子。在第-6、0、7、14、21、28、35、42、50和57天采集血清样本。IFAT比r-ELISA和MAT更早检测到抗弓形虫抗体。IFAT在第35天（Log10 = 2.9）和MAT在第35天（Log10 = 3.5）的抗体水平平均值较高，r-ELISA在第42天（OD = 0.797）的抗体水平平均值较高。接种后第57天，MAT中的抗体水平仍保持较高，而r-ELISA和IFAT中的抗体水平有下降趋势。以IFAT作为“金标准”，r-ELISA显示出比MAT更高的患病率（73.3%）、敏感性（94.3%）、阴性预测值（83.3%）和准确性（95.6%）。计算了各检测方法之间的kappa一致性，r-ELISA×IFAT显示出最佳结果（kappa = 0.88，p < 0.001）。在r-ELISA中研究了与米氏肉孢子虫的交叉反应，OD平均值为0.163±0.035（n = 65）。此外，接种肉孢子虫的动物在r-ELISA中均无阳性反应。我们的结果表明，r-ELISA可能是猪弓形虫感染血清学检测的一种良好方法。
