Type III interferons: Balancing tissue tolerance and resistance to pathogen invasion

Area of Science:

• Immunology
• Virology
• Microbiology

Background:

• Type III interferons (IFNs), also known as IFN-λ, are the most recently identified members of the IFN family.
• Previously, their functions were considered redundant with type I IFNs.
• Emerging evidence suggests unique roles for IFN-λ, particularly at mucosal surfaces.

Purpose of the Study:

• To highlight the distinct protective functions of IFN-λ at host barriers.
• To elucidate the mechanisms underlying IFN-λ's unique immunomodulatory properties.
• To discuss the balance between tissue tolerance and immune resistance mediated by IFN-λ.

Main Methods:

• Review of recent scientific literature on Type III IFNs.
• Analysis of IFN-λ receptor expression patterns.
• Examination of IFN-λ's immunomodulatory effects on epithelial and immune cells.

Main Results:

• IFN-λ exhibits restricted receptor expression, primarily on epithelial cells and specific immune cells.
• This restricted expression underpins its role as a primary defender of mucosal barrier integrity.
• IFN-λ possesses unique immunomodulatory properties distinct from Type I IFNs.

Conclusions:

• IFN-λ plays a specialized role in host defense at mucosal barriers.
• It uniquely balances the need for tissue tolerance with immune resistance against viral and bacterial threats.
• Understanding IFN-λ's functions is key to developing new strategies against mucosal infections.