# Novel recombinant protein immunoassays for the diagnosis and monitoring of toxocariasis in children living in the United States.

> **NIH NIH R03** · BAYLOR COLLEGE OF MEDICINE · 2024 · $80,250

## Abstract

Project Summary/Abstract
Toxocariasis, caused by the dog and cat roundworm (Toxocara canis or T. cati), is the most common zoonotic
helminth infection in children living in the United States (US). Toxocariasis disproportionately affects children
from underserved communities in the US, with the highest prevalence of disease in non-Hispanic Black children
(up to 21%). Toxocariasis manifests as distinct clinical syndromes leading to life-long morbidity from epilepsy,
asthma, and blindness. Thus, toxocariasis is an important contributor to child health disparities in the US. Despite
the significant life-long morbidity, toxocariasis remains underdiagnosed in the US in large part due to limitations
of the standard-of-care Toxocara diagnostic assay, an enzyme immunoassay (EIA) that detects host antibody
against T. canis excretory-secretory (TES) crude antigen. An improved Toxocara diagnostic assay would
facilitate accurate diagnosis and evaluate treatment response in children to prevent life-long morbidity. Given
the scalability and reproducibility, recombinant proteins are an exciting technology for improving Toxocara
diagnostics. Our state-of-the art laboratory, which routinely creates recombinant proteins, generated a T. canis
cDNA library to evaluate Toxocara antigens. Immunoscreening of the T. canis cDNA library with Toxocara
infected human sera identified T. canis C-type lectins (Tc-CTL-1 and Tc-CTL-2) as the most immunodominant
antigens. We subsequently identified the Tc-CTL-1 homolog in T.cati (Tca-CTL-1) with 93% sequence identity.
Using recombinant protein technology, we developed a multiplex recombinant protein Luminex immunoassay
and enzyme linked immunosorbent assay (ELISA) using Tc-CTL-1, Tc-CTL-2, Tca-CTL-1. The overall objective
of this project is to evaluate the diagnostic performance and potential for post-treatment monitoring of two new
multiplex immunoassays based on three, scalable recombinant proteins. We hypothesize that both multi-plex
immunoassays, utilizing the three recombinant proteins (rTc-CTL-1, rTc-CTL-2 and rTca-CTL-1), will have
improved test performance for diagnosis of toxocariasis compared to TES EIA and will permit the evaluation of
anthelminthic treatment monitoring in children. To evaluate this hypothesis, we will first determine the
performance characteristics of the two multiplex immuno-assays compared to TES EIA (standard of care) and
TES-immunoblot (TES-Blot; gold standard). Second, using both immunoassays we will quantitate total IgG and
IgG subtypes in peri-treatment sera collected from a longitudinal cohort of children with toxocariasis living in
Houston, TX. Achievement of our aims will result in at least one accurate, low-cost, scalable multiplex
immunoassay for the diagnosis and post-treatment monitoring of toxocariasis in children.

## Key facts

- **NIH application ID:** 10868718
- **Project number:** 5R03AI173826-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Jill Elizabeth Weatherhead
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $80,250
- **Award type:** 5
- **Project period:** 2023-06-16 → 2025-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10868718

## Citation

> US National Institutes of Health, RePORTER application 10868718, Novel recombinant protein immunoassays for the diagnosis and monitoring of toxocariasis in children living in the United States. (5R03AI173826-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10868718. Licensed CC0.

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