Deimmunization of flagellin for repeated administration as a vaccine adjuvant

Koemchhoy Khim,Kwangjoon Jeong,Joon Haeng Rhee,Shee Eun Lee,Yoonjoo Choi,Yong Jun Bang,Youn Suhk Lee,Sao Puth

doi:10.1038/s41541-021-00379-4

Koemchhoy Khim, Kwangjoon Jeong + Show 6 more

Open Access

https://doi.org/10.1038/s41541-021-00379-4

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Abstract

Flagellin, a protein-based Toll-like receptor agonist, is a versatile adjuvant applicable to wide spectrum of vaccines and immunotherapies. Given reiterated treatments of immunogenic biopharmaceuticals should lead to antibody responses precluding repeated administration, the development of flagellin not inducing specific antibodies would greatly expand the chances of clinical applications. Here we computationally identified immunogenic regions in Vibrio vulnificus flagellin B and deimmunized by simply removing a B cell epitope region. The recombinant deimmunized FlaB (dFlaB) maintains stable TLR5-stimulating activity. Multiple immunization of dFlaB does not induce FlaB-specific B cell responses in mice. Intranasally co-administered dFlaB with influenza vaccine enhanced strong Ag-specific immune responses in both systemic and mucosal compartments devoid of FlaB-specific Ab production. Notably, dFlaB showed better protective immune responses against lethal viral challenge compared with wild type FlaB. The deimmunizing B cell epitope deletion did not compromise stability and adjuvanticity, while suppressing unwanted antibody responses that may negatively affected vaccine antigen-directed immune responses in repeated vaccinations. We explain the underlying mechanism of deimmunization by employing molecular dynamics analysis.

Highlights

Flagellin is a representative protein-based pathogen-associated molecular pattern (PAMP) cognitively recognized by Toll-like receptor-5 (TLR5) [1, 2]
We previously reported that bacterial flagellin, Vibrio vulnificus FlaB, is a versatile adjuvant applicable to wide spectrum of vaccines and immunotherapies [7,8,9,10]
We determined biodistribution of FlaB or deimmunized FlaB (dFlaB) in inguinal lymph node and popliteal lymph node after footpad injection. Both FlaB and dFlaB localized in the draining iLN and pLN with comparable levels in fluorescence intensity (P > 0.05 for FlaB vs dFaB). These results clearly indicate that in vivo-administered dFlaB distributed in the draining lymph nodes (dLNs) as compared with wild type (WT) FlaB

Summary

INTRODUCTION

Flagellin is a representative protein-based pathogen-associated molecular pattern (PAMP) cognitively recognized by Toll-like receptor-5 (TLR5) [1, 2]. Three- or five-days after the virus challenge, groups of mice immunized with dFlaB-adjuvanted vaccine showed faster body weight recovery (Fig. 6a) This result clearly suggests that deimmunization potentiates immune modulatory function of flagellin against lethal infection and the dFlaB would have advantage over WT FlaB as a vaccine adjuvant with virtues other than antibodynoninducing characteristics. It will be interesting, in future studies, to check the ability of dFlaB in inducing trained innate immunity [4,5,6] or cell mediated immunity against viral antigens

DISCUSSION

Computational methods

Findings

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