Sandwich ELISA detection of excretory-secretory antigens of Toxocara canis larvae using a specific monoclonal antibody.

We produced a new monoclonal antibody (mAb) to the excretory-secretory (ES) antigens of Toxocara canis larvae. The mAb (IgG1) reacts specifically with the 120 kDa protein of many ES molecules and does not have any cross-reactivity with adult T. canis antigens. Sandwich ELISA to detect the ES antigens was performed using the mAb and rabbit polyclonal antiserum. The lower limit for the detection of ES antigen was 4 ng/ml; assay was proportional within a concentration range of 4 ng/ml to 1 microg/ml of ES antigen. This assay system may prove valuable when seeking to quantify parasite burden early in infection and when determining the efficacy of anthelmintic treatment.