Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype

Abstract The antimicrobial-resistant (AMR) Klebsiella pneumoniae (Kp) poses an enormous threat to human health, with O2 serotypes accounting for up to 35–59% of infections. Although the O-polysaccharide (OPS) of the Kp O2 serotype can be used as an antigen target for vaccine preparation, its simple...

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Main Authors: Peng Sun, Chao Pan, Huifang Xu, Bo Liu, Jingqin Ye, Kangfeng Wang, Yan Zhang, Ting Li, Li Zhu, Yating Wang, Hengliang Wang, Jun Wu
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:npj Vaccines
Online Access:https://doi.org/10.1038/s41541-025-01187-w
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author Peng Sun
Chao Pan
Huifang Xu
Bo Liu
Jingqin Ye
Kangfeng Wang
Yan Zhang
Ting Li
Li Zhu
Yating Wang
Hengliang Wang
Jun Wu
author_facet Peng Sun
Chao Pan
Huifang Xu
Bo Liu
Jingqin Ye
Kangfeng Wang
Yan Zhang
Ting Li
Li Zhu
Yating Wang
Hengliang Wang
Jun Wu
author_sort Peng Sun
collection DOAJ
description Abstract The antimicrobial-resistant (AMR) Klebsiella pneumoniae (Kp) poses an enormous threat to human health, with O2 serotypes accounting for up to 35–59% of infections. Although the O-polysaccharide (OPS) of the Kp O2 serotype can be used as an antigen target for vaccine preparation, its simple structure (only galactose repeats) makes it difficult to generate effective antibody responses and protection. Here, we prepared a novel Kp O2 OPS bioconjugate nanovaccine using protein glycan coupling technology (PGCT) and a SpyCatcher/SpyTag (SC/ST) orthogonal assembly system. The hepatitis B virus core antigen (HBc), which can assemble into nanoparticles, was used as a carrier to display OPS on its surface, allowing the bioconjugate to reach the nanoscale. The HBc-OPS exhibited attractive stability without aggregation or degradation for up to 10 months. A series of mouse experiments revealed the OPS-specific antibody activation ability of HBc-OPS and its protective effect against different infection doses. In particular, when coadministered with the AS03 adjuvant, all the mice were protected from higher doses of lethal attacks. Through in vitro and in vivo experiments, we found that the addition of AS03 further promoted the humoral immune response by stimulating increased levels of cytokines and T follicular helper (Tfh), germinal center B (GC B), and antigen-specific memory B cells. Moreover, we found that the use of AS03 as an adjuvant can provide a better protective effect than commonly used CpG-based adjuvants. Therefore, we have developed an attractive, stable, and effective bioconjugate nanovaccine against the Klebsiella pneumoniae O2 serotype. This bioconjugate nanovaccine design greatly potentiated the immunogenicity of polysaccharides, and the orthogonal modular assembly strategy reduced the technical difficulty of bioconjugate nanovaccine preparation, both of which could be applicable to the development of OPS conjugate vaccines for serotypes with low immunogenicity.
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spelling doaj-art-2101156c3e694a2bae94ff3dc99c39072025-08-20T03:03:23ZengNature Portfolionpj Vaccines2059-01052025-07-0110111110.1038/s41541-025-01187-wModular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotypePeng Sun0Chao Pan1Huifang Xu2Bo Liu3Jingqin Ye4Kangfeng Wang5Yan Zhang6Ting Li7Li Zhu8Yating Wang9Hengliang Wang10Jun Wu11School of Basic Medical Sciences, Tsinghua UniversityLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologySchool of Basic Medical Sciences, Tsinghua UniversitySchool of Basic Medical Sciences, Tsinghua UniversityLaboratory of Advanced Biotechnology, Beijing Institute of BiotechnologyAbstract The antimicrobial-resistant (AMR) Klebsiella pneumoniae (Kp) poses an enormous threat to human health, with O2 serotypes accounting for up to 35–59% of infections. Although the O-polysaccharide (OPS) of the Kp O2 serotype can be used as an antigen target for vaccine preparation, its simple structure (only galactose repeats) makes it difficult to generate effective antibody responses and protection. Here, we prepared a novel Kp O2 OPS bioconjugate nanovaccine using protein glycan coupling technology (PGCT) and a SpyCatcher/SpyTag (SC/ST) orthogonal assembly system. The hepatitis B virus core antigen (HBc), which can assemble into nanoparticles, was used as a carrier to display OPS on its surface, allowing the bioconjugate to reach the nanoscale. The HBc-OPS exhibited attractive stability without aggregation or degradation for up to 10 months. A series of mouse experiments revealed the OPS-specific antibody activation ability of HBc-OPS and its protective effect against different infection doses. In particular, when coadministered with the AS03 adjuvant, all the mice were protected from higher doses of lethal attacks. Through in vitro and in vivo experiments, we found that the addition of AS03 further promoted the humoral immune response by stimulating increased levels of cytokines and T follicular helper (Tfh), germinal center B (GC B), and antigen-specific memory B cells. Moreover, we found that the use of AS03 as an adjuvant can provide a better protective effect than commonly used CpG-based adjuvants. Therefore, we have developed an attractive, stable, and effective bioconjugate nanovaccine against the Klebsiella pneumoniae O2 serotype. This bioconjugate nanovaccine design greatly potentiated the immunogenicity of polysaccharides, and the orthogonal modular assembly strategy reduced the technical difficulty of bioconjugate nanovaccine preparation, both of which could be applicable to the development of OPS conjugate vaccines for serotypes with low immunogenicity.https://doi.org/10.1038/s41541-025-01187-w
spellingShingle Peng Sun
Chao Pan
Huifang Xu
Bo Liu
Jingqin Ye
Kangfeng Wang
Yan Zhang
Ting Li
Li Zhu
Yating Wang
Hengliang Wang
Jun Wu
Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
npj Vaccines
title Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
title_full Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
title_fullStr Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
title_full_unstemmed Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
title_short Modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against Klebsiella pneumoniae O2 serotype
title_sort modular assembly and immunological evaluation of a promising bioconjugate nanovaccine against klebsiella pneumoniae o2 serotype
url https://doi.org/10.1038/s41541-025-01187-w
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