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

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 <i>E. coli</i>. 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.