Adjuvants in Allergen-Specific Immunotherapy: Modulating and Enhancing the Immune Response.

Area of Science:

• Immunology
• Allergology
• Pharmacology

Background:

• Allergen-specific immunotherapy (AIT) is the only treatment modifying the natural course of allergic diseases.
• Adjuvants enhance immune response in AIT, with current products using aluminum hydroxide, calcium phosphate, microcrystalline tyrosine (MCT), or monophosphoryl lipid A (MPL).
• First-generation adjuvants (aluminum hydroxide, calcium phosphate, MCT) primarily act as delivery systems, while MPL is a second-generation immunostimulatory agent.

Purpose of the Study:

• To evaluate the efficacy of different adjuvants in AIT.
• To compare the effects of aluminum hydroxide versus newer adjuvants like MPL and immunostimulatory sequences (ISSs) on allergic responses.

Main Methods:

• A murine model of allergic bronchial inflammation was used, with mice sensitized to olive pollen.
• Mice were treated with olive pollen combined with either aluminum hydroxide or bacterial derivatives (MPL or ISSs).
• Specific IgE levels and bronchial hyperreactivity were measured.

Main Results:

• Treatment with aluminum hydroxide resulted in significantly higher specific IgE levels.
• Treatment with MPL or ISSs significantly reduced specific IgE levels and improved bronchial hyperreactivity.
• MPL and ISSs demonstrated superior efficacy compared to aluminum hydroxide in this model.

Conclusions:

• Second-generation adjuvants like MPL and ISSs are more effective than first-generation adjuvants such as aluminum hydroxide for AIT.
• MPL and ISSs offer a promising therapeutic strategy for allergic diseases by modulating immune responses.
• Further research into novel adjuvants is warranted to improve AIT efficacy.