2188 nonspecific, and include severe headache, hydrocephalus, blindness, epilepsy, and various neurological symptoms (Del Brutto 2005). NCC is a major cause of adult-onset epilepsy in areas where T. solium is prevalent (Flisser 1994). Moreover, in endemics countries, T. solium has been identified as the primary etiological agent of epileptic seiz- ures, accounting for 30–50% of all cases of late-onset epi- lepsy (Lescano et al. 2009). Diagnosis of NCC is complicated because of the unspe- cific clinical manifestation of this disease. Accurate diagno- sis can be achieved by use of neuroimaging methods such as magnetic resonance imaging (MRI) and computed tomog- raphy (CT), followed by a confirmatory serological test (Carpio et al. 1998). Unfortunately, in countries where T. solium is endemic, radio-imaging methods are seldom af- fordable and therefore inaccessible to the population at risk (Diaz et al. 1992). The laboratory diagnosis of cysticercosis is based on serological detection of antibodies against cys- ticerci (Deckers and Dorny 2010). Enzyme-linked immuno- assay (ELISA) and enzyme-linked immunoelectrotransfer blot (EITB) are the most frequently used immunodiagnostic tests for human cysticercosis (Dorny et al. 2003); both those methods are specific and sensitive, but they also have the disadvantage of requiring expensive, specialized equipment that must be run by skilled technicians (Deckers and Dorny 2010; Tsang et al. 1989). Thus, there is a continuing need for alternative diagnostic methods that are practical, repro- ducible, and economical, and also reduce the use of crude material (Deckers and Dorny 2010; Lundstrom et al. 2010; Salazar-Anton and Lindh 2011). Applying recombinant DNA technology can generate antigenic proteins that can serve as simplified, low-cost substitutes for native antigens. As an example of this, the recombinant form of the Tsol-p27 protein identified in T. solium cysticerus might prove useful as a target for diagnostic tools (Salazar-Anton and Lindh 2011). Our aim here was to compare results obtained with an immunodot blot assay based on the Tsol-p27 protein and different immunodiaganostic formats and antigens, using an EITB that we regarded as the gold standard method (Tsang et al. 1989). Materials and methods Serum sample collection A total of 100 human serum samples were collected from epileptic patients who attended the health centers of the Departments of Chinandega and Rosita in Nicaragua be- tween March and August 2010.The inclusion criteria for epileptic patients were based on clinical signs, symptoms (including seizure unrelated to withdrawal of drugs or Parasitol Res (2012) 110:2187–2191 alcohol), physical examination, epidemiologic information, and other associated risk factors. In addition, 60 serum samples with positive (30 sera) or negative (30 sera) indirect immunofluorescence (IF) serology for Chagas disease were included. All sera were stored at −20°C until used. The study protocol was approved by the Ethics Committee of the Faculty of Medical Science at the National Autonomous University of Nicaragua-León (UNAN-León). Expression and purification of recombinant Tsol-p27 and TsolHSP36 proteins The process of cloning the Tsol-p27 and TsolHSP36 antigens has been described previously (Salazar-Anton and Lindh 2011). In short, the genes corresponding to the Tsol-p27 and TsolHSP36 antigens were inserted into the plasmid vector pGEX-4T-1 (Amersham Pharmacia) downstream of glutathi- one S-transferase (GST). Both recombinant proteins were expressed in Escherichia coli BL21 (Invitrogen) and purified. In addition to the purification step with glutathione-agarose beads, Tsol-p27 antigen was further purified using his-selected nickel magnetic beads (Sigma). The resin was equilibrated with a buffer containing 50 mM sodium phosphate (pH 8.0), 0.3 M sodium chloride, and 10 mM imidazole, and then eluted with a higher concentration of imidazole (250 mM). The histidine-containing proteins were separated from the fraction by applying a magnetic separator to the mixed solution. The antigen purity was analyzed by 10% SDS PAGE and visual- ized by staining with Coomassie Brilliant Blue. EITB (commercial) EITB was performed according to the procedure recommen- ded by the manufacturer (LDBIO Diagnostic, Lyon, France). Antibody-detection ELISA (commercial) A commercial ELISA was used according to the manufac- turer’s instructions (Cypress Diagnostics). This test detected the presence of IgG antibodies against T. solium cysticerci in serum samples. A spectrophotometer (450 nm) was used to obtain optical density reading. Various controls were used for the validity of the ELISA including antibody blank, negative control serum, and positive control serum. The reaction threshold was 0.600. Values ≥0.600 were consid- ered positive for cysticercosis. Western blot analysis of Tsol-p27 and TsolHSP36 antigens (in house) The recombinant antigens were separated by 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS- PAGE) and transferred onto nitrocellulose membranes (GE