Evaluation of an immunodot blot technique for the detection of antibodies against Taenia solium larval antigens

Immunodiagnostic tests represent an important tool for diagnosis of cysticercosis, the disease caused by cysticerci of Taenia solium. Accurate diagnosis of neurocysticercosis (NCC) requires costly neuroimaging techniques (magnetic resonance imaging and computed tomography), which are seldom affordable for people in endemic countries. Hence, new low-cost diagnostic methods offering good sensitivity and specificity are needed. Here, we studied four immunodiagnostic tests immunodot blot Tsol-p27, a commercial ELISA, and Western blot Tsol-p27/TsolHSP36, and compared them with a commercial enzyme-linked immunoelectrotransfer blot (EITB) that we regarded as the gold standard method. The analyzed serum samples were obtained from 160 patients: 94 epileptics suspected of NCC, six individuals confirmed NCC-positive, and 60 with positive (30) or negative (30) serology for Chagas diseases. Of the 100 serum samples from epileptic patients, 13 were positive and 87 negative by EITB. Compared to Western blot Tsol-p27, immunodot blot Tsol-p27 offered similar specificity (97.8% vs. 95.6%) but better sensitivity (86.7% vs. 76.4%). The ELISA was similar to the immunodot blot Tsol-p27 regarding both sensitivity and specificity. Western blot TsolHSP36 provided the lowest sensitivity (61.9%) and specificity (86.1%). None of the antibodies in the serum samples from the Chagas control groups were recognized by immunodot blot Tsol-p27. Our results indicate that the immunodot blot Tsol-p27 provides good sensitivity and specificity. Furthermore, considering the simplicity and low cost of this test, it might be preferable as a diagnostic method in poorly equipped laboratories in endemic countries

Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine

Background: Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis.Methodology/ Principal Findings: In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. on the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms.Conclusions/ Significance: These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates

Reactivty in ELISA A and Dot-Blot of purified GP24, an immunodomiant antigen of Taenia-solium, for the diagnosis of human neurocysticercosis

In this paper we report the purification of GP24, one of the seven specific and highly antigenic Taenia solium glycoproteins previously identified by Western blot (WB) with serum, cerebrospinal fluid (CSF) and saliva samples from patients with neurocysticercosis (NC). GP24 was purified and evaluated in ELISA and dot blot for diagnosis. A lentil-lectin-bound glycoprotein fraction (LL-GP) from T. solium cysticerci was submitted to polyacrylamide gel electrophoresis, and the band that corresponded to GP24 was sliced, minced and electroeluted; an aliquot was used to immunize a rabbit, and the antiserum obtained was analysed by WB against LL-GP fraction; only GP24 was detected. ELISA and dot blot were performed with purified GP24 and serum and CSF samples from patients with NC that were previously positive for GP24 in WB and control samples; the latter were negative, while ail NC samples were positive. To test for specificity, purified GP24 was incubated in dot blot against 44 sera from patients with other parasitic diseases; no positive reactions were found. Results indicate that GP24 was adequately purified and retained its reactivity: thus in combination with ELISA or dot blot may facilitate immunodiagnosis of NC

Diagnostic of human cysticercosis by ELISA

An analysis of immunodiagnositc data for human cysticercosis by ELISA in 1 052 cerebrospinal fluid (CSF) and serum samples obtained directly from patients or their physicians from different hospitals during 1989-1991, as a result of the diagnostic support service that has been offered to the medical community since 1976, was performed. Overall positivity was 18 per cent. This value was slightly lower when only CSF was analysed (14%) and lowest in the case of serum samples (4%). Analysis of the CSF positivity in ELISA with respect to imaging findings yielded a predictive value of 93 per cent while in cases of excision of cysticerci by neurosurgery 67 per cent sensitivity was obtained. The high positive predictive value, the specificity and the sensitivity of ELISA indicate that this assay is useful to confirm the imaging diagnosis of neurocysticercosis when CSF is used or it can be used as a diagnostic alternative when imaging studies are not available