Evaluation of excretory-secretory and partially purified antigens of adult toxocara canis against human toxocariasis by elisa and immunoblot

Abstract

This study aimed to evaluate antigens prepared from adult Toxocara canis worms against human toxocariasis. Individual female and male worms were provided as crude somatic extract, partially somatic extract by Sephacryl S-200 chromatography and excretory-secretory (ES) products. All antigens were evaluated for sensitivity and specificity by ELISA and Western blot. ELISA using crude somatic antigen showed 97.6% sensitivity, with poor specificity. The peak 1 sensitivity of female and male somatic antigens was 95.1% and 92.7%, respectively, with specificity of 46.7% and 39.8%, respectively. The male peak 2 antigens showed 51.2% sensitivity and 67.8% specificity. The female and male ES antigens showed 95.0% and 87.8% sensitivity, respectively, and with low specificity (42.6% and 39.9%, respectively). Immunoblot using female crude somatic antigen revealed 52 kDa, which was not found in negative control or heterologous sera. However it was found in only 4 of 15 toxocariasis sera. Female 33 kDa ES antigen was found in 7 of 15 toxocariasis sera, but it cross-reacted with gnathostomiasis, angiostrongyliasis, strongyloidiasis and capillariasis. Male crude somatic and ES antigens did not demonstrate any diagnostic band among the human sera tested. All antigens in this study needed more advanced purification techniques to obtain higher specificity.