# Engineering Epitope-Specific IgY Antibodies to Neutralize the Major Fel d 1 Allergen in Cats

## TL;DR

This study shows that IgY antibodies can reduce allergen levels in cats, offering a new approach to managing cat allergies.

## Contribution

A novel strategy using epitope-specific IgY antibodies to neutralize the major cat allergen Fel d 1 is developed and tested.

## Key findings

- Anti-cFel d 1 IgY-enriched yolk powder reduced salivary Fel d 1 in cats by 30–71%.
- High-titer specific antibodies were produced in mice and hens after immunization with recombinant cFel d 1.
- T-cell epitopes of Fel d 1 were successfully predicted and expressed in E. coli.

## Abstract

Approximately 10–24% of people suffer from a cat allergy. Fel d 1, the major allergen, triggers reactions in approximately 94% of sensitized individuals. Current therapeutic strategies for allergic diseases primarily involve medication or immunotherapy to alleviate symptoms, which are often burdened by low efficacy, high cost, and extended duration, posing significant challenges for patients. In contrast, IgY antibodies offer a promising alternative by reducing the level of allergens produced by cats. In this study, T-cell epitopes of Fel d 1 were predicted using ProPred/CTLpred, connected via a suitable linker (GGGGS), and expressed in E. coli. Immunization of mice and hens with recombinant cFel d 1 yielded high-titer specific antibodies (IgG: 1:301,500; IgY: 1:4,194,304). Cats administered anti-cFel d 1 IgY-enriched yolk powder (1–3% of diet) for four weeks exhibited a 30–71% reduction in salivary Fel d 1. These findings indicate that the allergen epitope-targeted IgY strategy effectively reduces allergen levels in cats, providing a promising basis for preventing and treating allergic conditions.