Preliminary study of Toxocara canis Recombinant C- type Lectin as a suitable antigen for serodiagnosis of human toxocariasis

The protein C-type lectin is secreted by the secondary-stage larve of Toxocara canis (T. canis). Its antigenic characteristics have been the subject of research. The recombinant pET-32a (+) plasmid containing the 660 bp sequence of T. canis C-type lectin gene was successfully synthesized, cloned, and expressed in Escherichia coli (DE3+). Serum samples were collected from 56 pet owners. Forty-four samples were negative and twelve samples were positive which were performed with a commercial ELISA kit. The same samples were also tested using dot blot and Western blot analysis prepared with recombinant CTL antigen (rCTL). The expression was confirmed by Sodium Dodecyl Sulfate (SDS-PAGE) and Western blot. The study results revealed that two samples, which tested negative in the ELISA analysis, were found to be positive when using the recombinant C-type lectin (rCTL) antigen in both dot blot and Western blot analyses. The overall test results showed a high level of agreement between the three methods, with Kappa coefficients of 1 and 0.9 for the comparisons. This indicates the potential of using recombinant CTL antigen, to detect positive samples that may be missed by E-S Antigen. The recombinant rCTL demonstrated higher sensitivity than the excretory-secretory Antigens, indicating its potential for improved serodiagnosis of human toxocariasis. The study proposes that the rCTL could be further evaluated in supplementary studies to improve and develop the diagnostic kits for toxocariasis.