TSLP promotes influenza-specific CD8+ T-cell responses by augmenting local inflammatory dendritic cell function.

Area of Science:

• Immunology
• Virology
• Cytokine Signaling

Background:

• Thymic stromal lymphopoietin (TSLP) is a cytokine primarily associated with T helper type 2 (Th2)-driven inflammatory diseases.
• The function of TSLP during viral infections, particularly in adaptive antiviral immunity, remains largely uncharacterized.
• While TSLP production is observed during viral infections in vitro, its in vivo role is unknown.

Purpose of the Study:

• To investigate the role of TSLP in antiviral immunity during influenza A infection.
• To elucidate the mechanisms by which TSLP influences virus-specific immune responses, particularly CD8+ T-cell activation and viral clearance.

Main Methods:

• Comparative analysis of immune responses in wild-type and TSLP receptor (TSLPR)-deficient mice following influenza A infection.
• Assessment of virus-specific CD8+ T-cell expansion, activation, and effector function in lung and lymph node tissues.
• Investigation of the cellular sources and molecular mechanisms mediating TSLP's effects on immune cells, including dendritic cells (DCs).

Main Results:

• TSLP is essential for the expansion and activation of virus-specific effector CD8+ T cells in the lungs of infected mice.
• TSLPR signaling on inflammatory dendritic cells (CD11b+) is critical for TSLP-mediated antiviral immunity.
• TSLP signaling enhances interleukin-15 (IL-15) production and CD70 expression on DCs, promoting CD8+ T-cell responses.
• TSLP promotes viral clearance in a TSLPR-dependent manner.

Conclusions:

• TSLP plays a novel and beneficial role in promoting viral clearance and adaptive antiviral immunity.
• TSLP orchestrates virus-specific CD8+ T-cell responses in the lung through mechanisms involving inflammatory DCs, IL-15, and CD70.
• These findings reveal the pleiotropic functions of TSLP beyond its known roles in allergic inflammation and highlight its importance in combating viral infections.