Fungal symbiont transmitted by free-living mice promotes type 2 immunity

Area of Science:

• Microbiology
• Immunology
• Gastroenterology

Background:

• The gut mycobiota plays a key role in intestinal homeostasis and immune function.
• Inconsistent fungal colonization in laboratory mice complicates studies on host-microbe interactions.

Purpose of the Study:

• To identify a dominant fungal commensal in mice.
• To investigate its role in host immunity and colonization resistance.

Main Methods:

• Fungal identification and colonization studies in wild and laboratory mice.
• Analysis of host immune responses, including type 2 immunity and eosinophilia.
• Investigation of molecular mechanisms of immune activation.

Main Results:

• Kazachstania pintolopesii was identified as a dominant fungal commensal in wild mice.
• Colonization is bacteria-independent, enhances resistance to other fungi, and evades immune surveillance.
• K. pintolopesii induces a type 2 immune response via epithelial IL-33 and IL-33-ST2 signaling.
• This immunity influences helminth infection resistance and gastrointestinal allergy.

Conclusions:

• Kazachstania pintolopesii is a significant mouse gut commensal.
• It serves as a valuable model for studying fungal commensalism and host immunity.
• Its presence in research facilities may impact experimental outcomes.