Deimmunization of flagellin adjuvant for clinical application

Area of Science:

• Immunology
• Microbiology
• Biochemistry

Background:

• Flagellin is a key bacterial ligand recognized by host pattern recognition receptors, including toll-like receptor 5 (TLR5) and the NAIP5/NLRC4 inflammasome.
• Specific domains of flagellin mediate distinct immune responses: the D1 domain binds TLR5, while the C-terminal region activates NAIP5/NLRC4 inflammasomes.
• Heterogeneous D2/D3 domains are highly immunogenic, posing challenges for therapeutic applications.

Purpose of the Study:

• To review strategies and advancements in deimmunizing flagellin derivatives.
• To maintain the immunomodulatory activity of flagellin mediated by TLR5 and NLRC4 signaling.
• To enable safe and effective clinical applications of flagellin-based therapeutics.

Main Methods:

• Analysis of flagellin structure-function relationships concerning immune receptor binding.
• Exploration of deimmunization techniques to reduce immunogenicity.
• Evaluation of preserved TLR5 and NLRC4 stimulating activities in modified flagellin.

Main Results:

• Identification of conserved TLR5-binding sequences in the D1 domain.
• Characterization of the C-terminal 35 amino acids' role in NAIP5-mediated inflammasome activation.
• Development of deimmunization approaches for flagellin derivatives.

Conclusions:

• Deimmunization of flagellin is crucial for mitigating reactogenicity and ensuring efficacy in repeated administrations.
• Preserving TLR5/NLRC4-mediated immune stimulation is achievable through targeted flagellin modification.
• Deimmunized flagellin holds promise for vaccine adjuvant and immunotherapeutic applications.