Transcutaneous immunization system using a hydrotropic formulation induces a potent antigen-specific antibody...

Area of Science:

• Immunology
• Dermatology
• Vaccinology

Background:

• Transcutaneous immunization (TCI) is a promising vaccination strategy with potential therapeutic applications.
• Developing effective TCI systems requires simple, non-invasive, and safe transdermal formulations.
• This study addresses the need for improved TCI formulations by exploring novel delivery systems.

Purpose of the Study:

• To develop a novel TCI system using a co-administration approach.
• To investigate the efficacy of a formulation combining a liposoluble absorption enhancer (propylene glycol monocaprylate, PGMC) with a protein antigen.
• To evaluate the role of sodium salicylate (NaSal) as a hydrotropic agent in improving antigen solubility and enhancing immune response.

Main Methods:

• Developed novel transdermal formulations containing hen lysozyme (HEL) and PGMC, solubilized with NaSal.
• Administered the TCI system without prior skin treatment or typical adjuvants.
• Assessed HEL-specific antibody response in a dose-dependent manner.
• Investigated NaSal's effect on antigen-presenting cells (APCs) in vitro, including MHC class II expression and cytokine production (IL-12, TNF-α).
• Evaluated the safety of the TCI system by checking for anaphylactic reactions.

Main Results:

• The TCI system with HEL, PGMC, and NaSal induced a substantial HEL-specific antibody response, even without potent adjuvants like cholera toxin.
• NaSal demonstrated adjuvant-like properties by enhancing MHC class II expression and IL-12/TNF-α production in dendritic cells stimulated with lipopolysaccharide.
• The TCI system did not induce any HEL-specific, IgE-dependent anaphylactic reactions, indicating a favorable safety profile.

Conclusions:

• The developed TCI system utilizing a hydrotropic formulation effectively and safely induces the desired immune response.
• This novel approach represents an advantageous method for improving TCI strategies.
• The findings suggest potential for simplified and safer vaccine delivery through TCI.