# Flagellin as a Versatile Adjuvant Platform: Genetic Fusion Approaches for Next-Generation Vaccines

## TL;DR

Flagellin, a bacterial protein, is a promising adjuvant for vaccines that can boost immune responses when genetically fused with antigens.

## Contribution

The paper highlights genetic fusion of antigens to flagellin as a novel platform for developing versatile and safe vaccines.

## Key findings

- Flagellin activates immune responses via Toll-like receptor 5, making it an effective adjuvant.
- Genetic fusion of antigens to flagellin enhances immune responses and enables diverse vaccination strategies.
- Flagellin-based vaccines have advanced to clinical trials, showing potential for multiple infectious diseases.

## Abstract

Flagellin is the main structural protein of the bacterial flagellum, responsible for the movement of flagellated bacteria. Flagellin activates Toll-like receptor 5, inducing both innate and adaptive immune reactions, which highlights its potential as a vaccine adjuvant, particularly efficient in case of administration via mucosal routes. Genetic fusion of an antigen to flagellin has been shown to enhance the immune responses against the antigen. The molecular architecture of flagellin provides versatile and robust adjuvant functionality, facilitating the development of diverse vaccination strategies against multiple diseases as recombinant protein-based vaccines demonstrate substantial advantages over conventional live-attenuated and inactivated vaccines in both developmental efficiency and safety profiles. We present a comprehensive overview of vaccine design strategies employing genetic fusion of antigens to flagellin for protection against various infectious diseases. The proven effectiveness of flagellin-based delivery has enabled several vaccine candidates to enter clinical trials.