Meira Cristina S, Costa-Silva Thais A, Vidal José E, Ferreira Isabelle M R, Hiramoto Roberto M, Pereira-Chioccola Vera L
Department of Parasitology, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
Department of Neurology, Instituto de Infectologia Emílio Ribas, São Paulo, SP, Brazil.
J Med Microbiol. 2008 Jul;57(Pt 7):845-850. doi: 10.1099/jmm.0.47687-0.
Despite the development of serological and molecular methods in recent years, the diagnosis of cerebral toxoplasmosis in human immunodeficiency virus (HIV)-infected patients still presents difficulties. In the present study, we investigated whether cerebral toxoplasmosis induced changes in the reactivity of serum toward Toxoplasma gondii excreted-secreted antigens (ESA) in order to develop an assay for evaluating HIV-infected patients with cerebral toxoplasmosis. The antigen selection was based on those produced by tachyzoites, since it is the form of the organism responsible for disseminating the infection, as well as stimulation of the humoral and cellular immune responses. By using an ELISA containing pooled ESA recovered from infected culture supernatants with tachyzoites-RH strain (ESA-ELISA), we found that ESA had a high specificity for sera from patients with cerebral toxoplasmosis. The reactions were compared with an ELISA using crude tachyzoites antigen, widely used in traditional serology. The assays were performed on 293 serum samples separated as follows: 100 sera from patients with cerebral toxoplasmosis and AIDS (symptomatic), 99 sera from individuals with chronic toxoplasmosis (asymptomatic) and 94 sera from healthy individuals without toxoplasmosis (control). The crude tachyzoite antigen in ELISA was able to distinguish both groups of sera with toxoplasmosis, as similar reactivity were observed in sera from patients with cerebral toxoplasmosis and those from chronic individuals. In contrast, ESA-ELISA distinguished sera from symptomatic and asymptomatic individuals (three times more reactive in the former group, 12.6 versus 4.2). The assays were reproducible based on immunoblotting and statistical analysis. These data suggest the utility of ESA-ELISA in the diagnosis of cerebral toxoplasmosis in HIV-infected patients, since it provided clear evidence that anti-ESA antibodies are present principally in patients with active infection. The absence of a significant amount of antibodies distinguished the patients without clinical symptoms of infection.
尽管近年来血清学和分子方法有所发展，但人类免疫缺陷病毒（HIV）感染患者的脑弓形虫病诊断仍存在困难。在本研究中，我们调查了脑弓形虫病是否会引起血清对弓形虫排泄-分泌抗原（ESA）反应性的变化，以便开发一种用于评估患有脑弓形虫病的HIV感染患者的检测方法。抗原选择基于速殖子产生的抗原，因为速殖子是负责传播感染以及刺激体液和细胞免疫反应的生物体形式。通过使用一种酶联免疫吸附测定（ELISA），该方法包含从感染了速殖子-RH株的培养上清液中回收的混合ESA（ESA-ELISA），我们发现ESA对脑弓形虫病患者的血清具有高度特异性。将这些反应与使用粗制速殖子抗原的ELISA进行比较，粗制速殖子抗原在传统血清学中广泛使用。对293份血清样本进行了检测，样本分类如下：100份来自患有脑弓形虫病和艾滋病（有症状）的患者的血清，99份来自患有慢性弓形虫病（无症状）的个体的血清，以及94份来自无弓形虫病的健康个体（对照）的血清。ELISA中的粗制速殖子抗原能够区分两组患有弓形虫病的血清，因为在脑弓形虫病患者的血清和慢性患者的血清中观察到了相似的反应性。相比之下，ESA-ELISA能够区分有症状和无症状个体的血清（前一组的反应性高3倍，分别为12.6和4.2）。基于免疫印迹和统计分析，这些检测具有可重复性。这些数据表明ESA-ELISA在HIV感染患者脑弓形虫病诊断中的实用性，因为它提供了明确的证据，表明抗ESA抗体主要存在于有活动性感染的患者中。没有大量抗体可区分没有感染临床症状的患者。
