A Mouse Model of Mild Clostridioides difficile Infection for the Characterization of Natural Immune Responses

Assaf Mizrahi (1, 2) , Gauthier Péan de Ponfilly (1, 2) , Diane Sapa (2) , Antonia Suau (3, 4) , Irène Mangin (3) , Aurélie Baliarda (5, 2) , Sandra Hoys (2, 6) , Benoît Pilmis (2, 1) , Sylvie Lambert (7, 8) , Anaïs Brosse (6, 2) , Alban Le Monnier (2, 1, 6)

1 hpsj - Groupe Hospitalier Paris Saint-Joseph
2 MICALIS - MICrobiologie de l'ALImentation au Service de la Santé
3 Metabiot - Metabiot
4 TIMC-TrEE - Translational microbial Evolution and Engineering
5 AgroParisTech
6 Université Paris-Saclay
7 PJSE - Paris Jourdan Sciences Economiques
8 PSE - Paris School of Economics

Background: We describe a model of primary mild-Clostridioides difficile infection (CDI) in a naïve host, including gut microbiota analysis, weight loss, mortality, length of colonization. This model was used in order to describe the kinetics of humoral (IgG, IgM) and mucosal (IgA) immune responses against toxins (TcdA/TcdB) and surface proteins (SlpA/FliC). (2) Methods: A total of 105 CFU vegetative forms of C. difficile 630Δerm were used for challenge by oral administration after dysbiosis, induced by a cocktail of antibiotics. Gut microbiota dysbiosis was confirmed and described by 16S rDNA sequencing. We sacrificed C57Bl/6 mice after different stages of infection (day 6, 2, 7, 14, 21, 28, and 56) to evaluate IgM, IgG against TcdA, TcdB, SlpA, FliC in blood samples, and IgA in the cecal contents collected. (3) Results: In our model, we observed a reproducible gut microbiota dysbiosis, allowing for C. difficile digestive colonization. CDI was objectivized by a mean weight loss of 13.1% and associated with a low mortality rate of 15.7% of mice. We observed an increase in IgM anti-toxins as early as D7 after challenge. IgG increased since D21, and IgA anti-toxins were secreted in cecal contents. Unexpectedly, neither anti-SlpA nor anti-FliC IgG or IgA were observed in our model. (4) Conclusions: In our model, we induced a gut microbiota dysbiosis, allowing a mild CDI to spontaneously resolve, with a digestive clearance observed since D14. After this primary CDI, we can study the development of specific immune responses in blood and cecal contents.

Mots clés: Clostridioides difficile; Immune response; Colonization factor; Toxins; Gut microbiota

Domaines: Santé; Maladies infectieuses; Bactériologie; Virologie; Santé publique et épidémiologie

Assaf Mizrahi, Gauthier Péan de Ponfilly, Diane Sapa, Antonia Suau, Irène Mangin, et al.. A Mouse Model of Mild Clostridioides difficile Infection for the Characterization of Natural Immune Responses. Microorganisms, 2024, 12 (10), pp.1933. ⟨10.3390/microorganisms12101933⟩. ⟨hal-04764178⟩