P-FN12, an H4R-Based Epitope Vaccine Screened by Phage Display, Regulates the Th1/Th2 Balance in Rat Allergic...

Area of Science:

• Immunology
• Allergology
• Vaccinology

Background:

• Allergic rhinitis (AR) is characterized by nasal inflammation, often treated by targeting histamine pathways.
• The histamine H4 receptor (H4R) presents a novel therapeutic target due to its presence on immune cells.
• Developing targeted therapies for AR remains a critical area of research.

Purpose of the Study:

• To identify a specific peptide targeting the H4R for potential therapeutic use in AR.
• To evaluate the efficacy of a P-FN12-based vaccine in an animal model of allergic rhinitis.
• To investigate the immunological mechanisms underlying the vaccine's therapeutic effects.

Main Methods:

• Selection of a specific H4R-binding peptide (P-FN12) from a random peptide library.
• Formulation of a P-FN12 + CTB@Lipo vaccine administered as nasal drops.
• Assessment of allergic symptoms, immunoglobulin E (IgE) levels, cytokine profiles (IFN-γ, IL-2, IL-4), and Th1:Th2 cell ratios in a rat model.

Main Results:

• The P-FN12 peptide demonstrated high affinity binding to H4R.
• The P-FN12 + CTB@Lipo vaccine significantly reduced allergic symptoms like sneezing and nasal rubbing in rats.
• Vaccine administration led to decreased OVA-specific IgE, reduced Th2 immunity markers (IL-4), and increased Th1 immunity markers (IFN-γ, IL-2), elevating the Th1:Th2 ratio.

Conclusions:

• The P-FN12 peptide is a specific H4R binder with therapeutic potential for allergic rhinitis.
• The P-FN12 + CTB@Lipo vaccine effectively suppresses allergic inflammation by modulating immune responses.
• This vaccine strategy shows promise for treating AR by shifting the immune balance from Th2 to Th1 dominance.