Nano-micro Combination: Overcoming Dual Intranasal Barriers to Elicit a Comprehensive Immune Response

Area of Science:

• Immunology
• Nanotechnology
• Biomaterials

Background:

• Intranasal immunization is crucial for preventing respiratory infections by inducing mucosal immunity.
• Nasal mucus and mucosal barriers limit the efficacy of traditional intranasal delivery systems.
• A novel delivery system is needed to enhance antigen residence time and cellular interaction.

Purpose of the Study:

• To develop and evaluate a particle-in-oil-in-water (POW) system for intranasal immunization.
• To overcome nasal barriers and improve antigen delivery and immune response.
• To assess the POW system's potential as an intranasal adjuvant.

Main Methods:

• Construction of a nano-micro composite particle-in-oil-in-water (POW) system.
• Utilizing flexible deformation and micron-scale structure for mucosal adherence.
• Employing fluorescence imaging and quantitative analysis to track antigen residence time and cellular interaction.
• Measuring sIgA, IgG antibody levels, and cytokine expression (IFN-γ, IL-4).

Main Results:

• POW significantly extended nasal antigen residence time from 2 to 6 hours.
• The flexible POW system enhanced cellular contact, permeation, and absorption.
• Intranasal immunization with POW induced 20-fold higher sIgA and 12-fold higher IgG than antigen alone.
• POW increased IFN-γ and IL-4 levels by 3.8-fold and 2.53-fold, respectively, outperforming injection immunization.

Conclusions:

• The POW system effectively overcomes nasal barriers, enhancing mucosal and systemic immunity.
• POW demonstrates superior immunogenicity compared to antigen alone and traditional injection methods.
• This particle-in-oil-in-water system shows promise as a novel intranasal adjuvant for vaccines against respiratory infections.