T1/ST2 promotes T helper 2 cell activation and polyfunctionality in bronchopulmonary mycosis

Area of Science:

• Immunology
• Infectious Diseases
• Allergy and Inflammation

Background:

• Cryptococcus neoformans infection is typically controlled by T helper 1 (Th1) immune responses.
• The mechanisms underlying nonprotective T helper 2 (Th2) immunity in pulmonary cryptococcosis remain unclear.
• Interleukin-33 (IL-33) is known to enhance Th2 immunity through its receptor, T1/ST2.

Purpose of the Study:

• To investigate the role of T1/ST2 in directing Th2 cell activation and polyfunctionality during Cryptococcus neoformans infection.
• To elucidate the mechanisms linking T1/ST2 signaling to allergic inflammation and impaired fungal control in pulmonary cryptococcosis.

Main Methods:

• Utilized a murine model of pulmonary C. neoformans infection.
• Assessed T1/ST2 expression and correlated it with Th2 activation markers (CD25, CD44, CD62L).
• Compared cytokine production (IL-5, IL-13) and polyfunctionality of T1/ST2(+) Th cells versus T1/ST2(-) or T1/ST2(-/-) Th cells.

Main Results:

• T1/ST2 expression positively correlated with the intensity of Th2 activation.
• Antigen-specific T1/ST2(+) Th cells were the primary source of IL-5 and IL-13, exhibiting enhanced polyfunctionality.
• T1/ST2-driven Th2 development led to defective pulmonary fungal control and contributed to allergic inflammation.

Conclusions:

• T1/ST2 signaling is a critical driver of Th2 cell activation and polyfunctionality in the context of allergic bronchopulmonary mycosis.
• The T1/ST2-mediated Th2 response compromises the host's ability to control C. neoformans infection, exacerbating pulmonary pathology.