Non-invasive transcutaneous influenza immunization using vaccine-loaded vaterite particles

Transcutaneous immunization receives much attention due to the recognition of a complex network of immunoregulatory cells in various layers of the skin. The elaboration of non-invasive needle-free approaches towards antigen delivery holds especially great potential here while searching for a hygienically optimal vaccination strategy. Here, we report on a novel protocol for transfollicular immunization aiming at delivery of an inactivated influenza vaccine to perifollicular antigen presenting cells without disrupting the stratum corneum integrity. Porous calcium carbonate (vaterite) submicron carriers and sonophoresis were utilized for this purpose. Transportation of the vaccine-loaded particles into hair follicles of mice was assessed in vivo via optical coherence tomography monitoring. The effectiveness of the designed immunization protocol was further demonstrated in an animal model by means of micro-neutralization and enzyme-linked immunosorbent assays. The titers of secreted virus-specific IgGs were compared to those obtained in response to intramuscular immunization using conventional influenza vaccine formulation demonstrating no statistically significant differences in antibody levels between the groups. The findings of our pilot study render the intra-follicular delivery of the inactivated influenza vaccine by means of vaterite carriers a promising alternative to invasive immunization.

Automated summary

Transcutaneous immunization is a promising non-invasive approach for delivering vaccines to antigen presenting cells in the skin. In this study, a novel protocol for transfollicular immunization using porous calcium carbonate carriers and sonophoresis was developed to deliver an inactivated influenza vaccine to perifollicular cells without disrupting the skin's barrier. In vivo monitoring demonstrated the successful transport of vaccine-loaded particles into hair follicles, and the effectiveness of the protocol was confirmed in an animal model through immune response assays. This study highlights the potential of intra-follicular delivery of vaccines as a less invasive alternative to traditional immunization methods.