ELISA and western blotting tests in the detection of IgG antibodies to Taenia solium metacestodes in serum samples in human neurocysticercosis.

A comparative study of total saline extract (SE) and cyst vesicular fluid (VF) of Taenia solium metacestodes by ELISA and Western blotting assay (WB) tests was conducted to detect IgG in sera for diagnosis of human cysticercosis. Sera were obtained and analysed by ELISA in 1 : 20 and 1 : 100 dilutions from 208 individuals: 22 confirmed neurocysticercosis (NC) (group 1), 101 suspected NC (group 2), 55 with various intestinal parasitosis (group 3) and 30 healthy individuals (group 4). The WB test was carried out on SE and VF extracts with and without reducing agent, 2-beta-mercaptoethanol (2-ME) in 20 sera of each group. WB using extracts without 2-ME and ELISA at 1 : 100 dilution were compared in 20 sera from each group; sensitivity and specificity were calculated using samples from groups 1, 3 and 4. By ELISA, in the 1 : 100 sera dilution reactivity was reduced for both antigens without changes in the sensitivity of the test. By WB, antigens treated with 2-ME demonstrated low specificity. For SE and VF antigens, the proteins of 24, 39-42, 47-52, 56, 64-68, 126-155 kDa and 18, 24, 26-28, 32-36, 47-52, 75 kDa, respectively, were considered immunodominant markers, with high indices of specificity, suggesting a profile for NC patients. However, as the sensitivity was found to be low, it might still not be a definitive test for NC when used alone. These data suggest WB as an indicative test to determine exposure to T. solium. ELISA and WB together may supply reliable results for the diagnosis of human cysticercosis, since appropriate purified antigens are not available yet.