Mucosal adjuvanticity and mucosal booster effect of colibactin-depleted probiotic Escherichia coli membrane vesicles

Hiroki Uchiyama; Toshifumi Kudo; Takehiro Yamaguchi; Nozomu Obana; Kenji Watanabe; Kimihiro Abe; Hidetaka Miyazaki; Masanori Toyofuku; Nobuhiko Nomura; Yukihiro Akeda; Ryoma Nakao

doi:10.1080/21645515.2024.2337987

Mucosal adjuvanticity and mucosal booster effect of colibactin-depleted probiotic Escherichia coli membrane vesicles

Hum Vaccin Immunother. 2024 Dec 31;20(1):2337987. doi: 10.1080/21645515.2024.2337987. Epub 2024 Apr 24.

Authors

Hiroki Uchiyama^{1

2}, Toshifumi Kudo², Takehiro Yamaguchi¹, Nozomu Obana^{3

4}, Kenji Watanabe⁵, Kimihiro Abe^{1

6}, Hidetaka Miyazaki^{7

8}, Masanori Toyofuku⁴, Nobuhiko Nomura⁴, Yukihiro Akeda¹, Ryoma Nakao¹

Affiliations

¹ Department of Bacteriology I, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.
² Department of Vascular Surgery, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
³ Tsukuba Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
⁴ Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan.
⁵ Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
⁶ Research Center for Drug and Vaccine Development, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.
⁷ Department of Oculoplastic, Orbital and Lacrimal Surgery, Aichi Medical University, Nagakute, Japan.
⁸ Department of Oral and Maxillofacial Surgery, Division of Oral Health Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.

Abstract

There is a growing interest in development of novel vaccines against respiratory tract infections, due to COVID-19 pandemic. Here, we examined mucosal adjuvanticity and the mucosal booster effect of membrane vesicles (MVs) of a novel probiotic E. coli derivative lacking both flagella and potentially carcinogenic colibactin (ΔflhDΔclbP). ΔflhDΔclbP-derived MVs showed rather strong mucosal adjuvanticity as compared to those of a single flagellar mutant strain (ΔflhD-MVs). In addition, glycoengineered ΔflhDΔclbP-MVs displaying serotype-14 pneumococcal capsular polysaccharide (CPS14⁺MVs) were well-characterized based on biological and physicochemical parameters. Subcutaneous (SC) and intranasal (IN) booster effects of CPS14⁺MVs on systemic and mucosal immunity were evaluated in mice that have already been subcutaneously prime-immunized with the same MVs. With a two-dose regimen, an IN boost (SC-IN) elicited stronger IgA responses than homologous prime-boost immunization (SC-SC). With a three-dose regimen, serum IgG levels were comparable among all tested regimens. Homologous immunization (SC-SC-SC) elicited the highest IgM responses among all regimens tested, whereas SC-SC-SC failed to elicit IgA responses in blood and saliva. Furthermore, serum IgA and salivary SIgA levels were increased with an increased number of IN doses administrated. Notably, SC-IN-IN induced not only robust IgG response, but also the highest IgA response in both serum and saliva among the groups. The present findings suggest the potential of a heterologous three-dose administration for building both systemic and mucosal immunity, e.g. an SC-IN-IN vaccine regimen could be beneficial. Another important observation was abundant packaging of colibactin in MVs, suggesting increased applicability of ΔflhDΔclbP-MVs in the context of vaccine safety.

Keywords: Administration route; Streptococcus pneumoniae; capsular polysaccharide; heterologous prime-boost immunization; immunogenicity; membrane vesicles; mucosal adjuvanticity; probiotic Escherichia coli; respiratory tract infection.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adjuvants, Immunologic* / administration & dosage
Administration, Intranasal
Animals
COVID-19 Vaccines / administration & dosage
COVID-19 Vaccines / immunology
Escherichia coli* / immunology
Female
Immunity, Mucosal*
Immunization, Secondary* / methods
Immunoglobulin A
Immunoglobulin G / blood
Immunoglobulin M
Mice
Mice, Inbred BALB C*
Peptides / immunology
Polyketides*
Probiotics* / administration & dosage

Substances

colibactin
Adjuvants, Immunologic
Polyketides
Immunoglobulin A
Peptides
Immunoglobulin G
Immunoglobulin M
COVID-19 Vaccines

Grants and funding

This work was supported by grants from KAKENHI of the Japan Society for the Promotion of Science (JSPS) [nos. 19K22644, 20K09943, 21KK0164, and 21K18284] and Ministry of Education, Culture, Sports, Science and Technology (MEXT) [no. 20H03861].