Generation and characterization of monoclonal antibodies specific for 18 kDa antigen from Taenia solium cysticerci.

The gene encoding a mature 18 kDa glycoprotein of Taenia solium cysticerci (Ts18) was cloned and bacterially expressed with a His-tagged fusion protein. Monoclonal antibodies (MAbs) against the recombinant Ts18 antigen were generated in vitro by routine murine hybridoma technique of fusing splenocytes, from BALB/c mice immunized with the vesicular fluid of T. solium cysticerci (TsVF), with mouse myeloma cells (SP2/0). The reactivity and specificity of these MAbs were evaluated by indirect ELISA and immunoblotting techniques. Three stable hybridoma clones, namely 3B11, 6C5, and 6G4, were screened using His-Ts18-based ELISA, and these showed two IgG1 isotypes and one IgM isotype. All MAbs reacted with His-Ts18 at molecular weight (MW) 12.8 kDa and the native antigen at MW 18 kDa in TsVF and whole larval extracts (WLE). In a dot blotting test, MAbs 6C5 and 6G4 showed no obvious cross-reactivity with heterologous vesicular fluids from other taeniid species, including Taenia saginata (TsaVF), Taenia pisiformis (TpVF), Taenia hydatigena (ThVF), Taenia multiceps (TmVF), and Echinococcus granulosus (EgVF). Immunofluorescent assays showed that MAb 6C5 specifically reacted with the Ts18 expressed from pEGFP-N1-Ts18-transfected HeLa cells. Immunolocalization analysis, using MAb 6C5 as a probe, indicated that Ts18 was present at high concentrations in the region of the larval sucker and spiral canal. The results indicate that the Ts18 protein is an abundantly secreted parasite protein and MAbs against it might provide a step forward for improving the diagnosis of porcine cysticercosis.