Winter, Kaitlin; Houle, Sébastien; Dozois, Charles M. 
ORCID: https://orcid.org/0000-0003-4832-3936 et Ward, Brian J.
(2024).
Multimodal vaccination targeting the receptor binding domains of Clostridioides difficile toxins A and B with an attenuated Salmonella Typhimurium vector (YS1646) protects mice from lethal challenge
Microbiology Spectrum
, nº e0310922.
DOI: 10.1128/spectrum.03109-22.
(Sous Presse)
Résumé
Developing a vaccine against Clostridioides difficile is a key strategy to protect the elderly. Two candidate vaccines using a traditional approach of intramuscular (IM) delivery of recombinant antigens targeting C. difficile toxins A (TcdA) and B (TcdB) failed to meet their primary endpoints in large phase 3 trials. To elicit a mucosal response against C. difficile, we repurposed an attenuated strain of Salmonella Typhimurium (YS1646) to deliver the receptor binding domains (rbd) of TcdA and TcdB to the gut-associated lymphoid tissues, to elicit a mucosal response against C. difficile. In this study, YS1646 candidates with either rbdA or rbdB expression cassettes integrated into the bacterial chromosome at the attTn7 site were generated and used in a short-course multimodal vaccination strategy that combined oral delivery of the YS1646 candidate(s) on days 0, 2, and 4 and IM delivery of recombinant antigen(s) on day 0. Five weeks after vaccination, mice had high serum IgG titers and increased intestinal antigen-specific IgA titers. Multimodal vaccination increased the IgG avidity compared to the IM-only control. In the mesenteric lymph nodes, we observed increased IL-5 secretion and increased IgA+ plasma cells. Oral vaccination skewed the IgG response toward IgG2c dominance (vs IgG1 dominance in the IM-only group). Both oral alone and multimodal vaccination against TcdA protected mice from lethal C. difficile challenge (100% survival vs 30% in controls). Given the established safety profile of YS1646, we hope to move this vaccine candidate forward into a phase I clinical trial.
| Type de document: | Article |
|---|---|
| Mots-clés libres: | Clostridioides difficile; Salmonella Typhimurium; chromosomal integration; humoral immunity; mucosal immunity; vaccination |
| Centre: | Centre INRS-Institut Armand Frappier |
| Date de dépôt: | 05 févr. 2024 05:48 |
| Dernière modification: | 05 févr. 2024 05:48 |
| URI: | https://espace.inrs.ca/id/eprint/14181 |
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