Epicutaneous immune modulation with Bet v 1 plus R848 suppresses allergic asthma in a murine model

Area of Science:

• Immunology
• Allergy Research
• Vaccine Adjuvant Development

Background:

• Allergen-specific immunotherapy aims to improve efficacy and safety by combining allergens with adjuvants.
• Polyadenylic-polyuridylic acid (poly(A:U)) and R848 (resiquimod) are agonists for TLR3 and TLR7, respectively, investigated for adjuvant potential.
• Birch pollen allergy is a common condition, and Bet v 1 is its primary allergen.

Purpose of the Study:

• To investigate the adjuvant effects of poly(A:U) and R848 in epicutaneous immunotherapy (EPI) for birch pollen allergy.
• To evaluate the impact of these adjuvants on immune responses and allergic asthma features.
• To determine the potential of R848 as an adjuvant for birch pollen-induced allergic asthma.

Main Methods:

• BALB/c mice underwent epicutaneous immunization (EPI) with recombinant Bet v 1 (rBet v 1) alone or with poly(A:U) or R848.
• Mice were sensitized and intranasally challenged with birch pollen extract to induce allergic asthma.
• Immune responses, including T cell activation, antibody production (IgG2a, IgE), and airway hyper-reactivity ( Penh), were assessed.

Main Results:

• EPI with rBet v 1 and R848 induced IFN-γ-producing CD4(+) T cells and Bet v 1-specific IgG2a antibodies.
• Prophylactic EPI with rBet v 1 and R848 inhibited active Bet v 1-specific IgE production.
• Both prophylactic and therapeutic EPI with rBet v 1 and R848 suppressed lung inflammation and airway hyper-reactivity (Penh).
• Poly(A:U) did not demonstrate significant adjuvant effects in suppressing asthmatic features.

Conclusions:

• Epicutaneous immunotherapy with rBet v 1 plus R848 promotes Th1 responses against Bet v 1.
• This combination therapy effectively suppresses allergic asthma symptoms induced by birch pollen.
• R848 shows promise as an adjuvant for epicutaneous immunotherapy in treating birch pollen-induced allergic asthma.