A Lateral Flow Rapid Test for Human Toxocariasis Developed Using Three Toxocara canis Recombinant Antigens

Am J Trop Med Hyg. 2018 Jan;98(1):32-38. doi: 10.4269/ajtmh.17-0632. Epub 2018 Jan 1.

Abstract

Laboratory diagnosis of toxocariasis is still a challenge especially in developing endemic countries with polyparasitism. In this study, three Toxocara canis recombinant antigens, rTES-26, rTES-30, and rTES-120, were expressed and used to prepare lateral flow immunoglobulin G4 (IgG4) dipsticks. The concordance of the results of the rapid test (comprising three dipsticks) with a commercial IgG-enzyme-linked immunosorbent assay (ELISA) (Cypress Diagnostics, Belgium) was compared against the concordance of two other commercial IgG-ELISA kits (Bordier, Switzerland and NovaTec, Germany) with the Cypress kit. Using Toxocara-positive samples, the concordance of the dipstick dotted with rTES-26, rTES-30, and rTES-120 was 41.4% (12/29), 51.7% (15/29), and 72.4% (21/29), respectively. When positivity with any dipstick was considered as an overall positive rapid test result, the concordance with the Cypress kit was 93% (27/29). Meanwhile, when compared with the results of the Cypress kit, the concordance of IgG-ELISA from NovaTec and Bordier was 100% (29/29) and 89.7% (26/29), respectively. Specific IgG4 has been recognized as a marker of active infection for several helminthic diseases; therefore, the two non-concordant results of the rapid test when compared with the NovaTec IgG-ELISA kit may be from samples of people with non-active infection. All the three dipsticks showed 100% (50/50) concordance with the Cypress kit when tested with serum from individuals who were healthy and with other infections. In conclusion, the lateral flow rapid test is potentially a good, fast, and easy test for toxocariasis. Next, further validation studies and development of a test with the three antigens in one dipstick will be performed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Helminth / immunology*
  • Antigens, Helminth / isolation & purification
  • Blotting, Western
  • Enzyme-Linked Immunosorbent Assay / methods
  • Humans
  • Reagent Kits, Diagnostic
  • Recombinant Proteins
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Toxocara canis / immunology*
  • Toxocariasis / diagnosis*
  • Toxocariasis / immunology

Substances

  • Antigens, Helminth
  • Reagent Kits, Diagnostic
  • Recombinant Proteins