Recombinant Hypoallergenic Cat Allergy Vaccines

• DOI: 10.1111/all.16542
• Publication Date: 2025-04-05T02:34:10Z
• Authors: Daria Trifonova; Mirela Curin; Margarete Focke‐T...; Zicheng Liu; Kristina Borochova; Pia Gattinger; Marianne van Hage; Hans Grönlund; Renata Kiss; Huey‐Jy Huang; Walter Keller; Ksenja Riabova; Antonina Karsonova; Michael Kundi; Inna Tulaeva; Daria Fomina; Alexander Karaulov; Rudolf Valenta

ABSTRACTBackgroundMolecular forms of allergen‐specific immunotherapy (AIT) for cat allergy are needed. Fel d 1, Fel d 4, and Fel d 7 are the most important cat allergens.MethodsIgE epitopes of Fel d 4 and Fel d 7 were mapped by blocking allergic patients' IgE binding with allergen peptide‐specific antisera. Five recombinant fusion proteins (PreS‐Cat 1‐PreS‐Cat 5) each containing hepatitis B virus (HBV)‐derived PreS as an immunological carrier and non‐allergenic peptides from the IgE binding sites of Fel d 1, Fel d 4, and Fel d 7 were expressed in Escherichia coli, purified, and characterized by mass spectrometry, circular dichroism (CD), and size exclusion chromatography. ImmunoCAP and basophil activation experiments demonstrated the hypoallergenic activity of PreS‐Cat 1–5. The ability of PreS‐Cat 1–5 to induce IgE‐blocking antibodies in rabbits was compared to three licensed allergen extract‐based AIT vaccines. PreS‐Cat 1‐5‐specific IgG antibodies were tested for inhibition of allergen‐specific IgE binding and specific basophil activation. T cell activation and induction of specific cytokine secretion by PreS‐Cat proteins were compared with cat allergens in PBMC cultures.ResultsRecombinant hypoallergenic, biochemically and structurally defined PreS‐Cat 1–5 were obtained. Two subcutaneous immunizations of rabbits with PreS‐Cat 1–5 induced equal (Fel d 1) or better (Fel d 4 and Fel d 7) antibodies (PreS‐Cat 5 > PreS‐Cat 1 > PreS‐Cat 3) blocking allergic patients' IgE binding to cat allergens than six to fifteen immunizations with allergen extract‐based vaccines. PreS‐Cat‐specific antibodies strongly inhibited specific basophil activation. PreS‐Cat 5 > PreS‐Cat 1 induced significantly more IL‐10 in cultured PBMCs from cat allergic patients than cat allergens.ConclusionsPreS‐Cat 5 and PreS‐Cat 1 are highly promising molecular vaccine candidates for AIT of cat allergy, combining Fel d 1‐, Fel d 4‐, and Fel d 7‐peptides in single PreS fusion proteins.