The PCR products were respectively cloned into the plasmid pGEX-4T-1 (GE Healthsystems, Uppsala, Sweden) and PET-28a (Qiagen, Dsseldorf, Germany) to construct recombinant plasmids, which were subsequently confirmed by sequencing

The PCR products were respectively cloned into the plasmid pGEX-4T-1 (GE Healthsystems, Uppsala, Sweden) and PET-28a (Qiagen, Dsseldorf, Germany) to construct recombinant plasmids, which were subsequently confirmed by sequencing. cases, the parasites do pose threats to individuals who are immunocompromised, such as HIV carriers [2]. It has been estimated that up to one third of the worlds populace has been infected by with an endemicity from around 10% to 70% [1,3-5] and the prevalence is usually higher in warm and humid areas [6-8]. In several studies, patients with schizophrenia were found to have a higher tendency of contamination [9-12], but there has been no conclusive correlation between contamination and psychiatric disease [13]. displays significant genetic diversity in different geographical regions [14-16]. Currently, toxoplasmosis is Aminophylline usually diagnosed primarily by demonstrating parasite-specific IgM or IgG antibodies in serum samples. Most of the commercially available tests use native antigens derived from the fast growing tachyzoites which may result in variations in accuracy of detection. Recombinant antigens have been suggested as diagnostic reagents but their reliability may need extensive Aminophylline experimental validation [17,18]. Further, remains dormant as bradyzoites in immune competent individuals, SERPINA3 which can convert to tachyzoites when the host immune defense system is usually compromised, and tachyzoites and bradyzoites do display different antigenic profiles [19]. Thus it is critical to select accurate antigens for diagnostic and epidemiological purposes. In this study, we investigated the level of anti-IgG and IgM in the sera of more than 800 Chinese individuals living in the southern and northern regions of China, comparing crude antigens of RH (Type I) and ME49 (Type II) strains and 12 recombinant antigens of either Type I or Type II specific antibodies in the same set of samples with different antigens. Methods Study populations and serum samples 880 serum samples from clinically healthy individuals were collected in Changchun, Daqing and Shanghai areas in China from July 2006 to June 2012 as described previously [20]. The sera were collected with the consent of the volunteers. The study was carried out with permission from the Ethical Committee of Institute of Zoonosis, Jilin University, China. Antigens Soluble native parasite antigens: tachyzoites of RH and ME49 strains were cultivated in BHK (baby hamster kidney) cell lines as described earlier [21]. Briefly parasites released from host cells were harvested, washed in PBS and lysed by sonication. The insoluble component such as cell debris was eliminated by centrifugation (12,000 rpm for 30 min) and the soluble proteins, respectively termed RH-Ag and ME49-Ag were collected and diluted to a final concentration of 1 1 mg/ml in PBS for the serological test. Recombinant antigens: To generate the recombinant antigens, the coding sequences of RH and ME49 strains and was used as the template for PCR amplification of the coding sequences. The PCR reaction was carried out in Aminophylline a 25 l reaction mixture made up of 10 M of each primer, 2.5 mM of each dNTP, 1.25 U of Ex Taq DNA polymerase (TAKARA), 0.5 g DNA template, and 1??Ex Taq buffer. The touchdown PCR was performed around the PCR System (Applied Biosystems, CA, USA) with a program of initial denaturation for 4 min at 94C; 35 cycles of 94C for 45 s, annealing for 45 s (initial temperature 61C, then decreasing by 0.3C/cycle), and 72C Aminophylline for 2 min; and a final extension at 72C for 10 min. The PCR products were respectively cloned into the plasmid pGEX-4T-1 (GE Healthsystems, Uppsala, Sweden) and PET-28a (Qiagen, Dsseldorf, Germany) to construct recombinant plasmids, which were subsequently confirmed by sequencing. The plasmids with correct sequences were transformed into BL21 qualified cells and the His-tag and GST-tag fusion proteins were expressed and purified according to a standard protocol as described [22]. They were respectively named as RH-rAg,.