Group 1 ILCs regulate T cell-mediated liver immunopathology by controlling local IL-2 availability

Area of Science:

• Immunology
• Hepatology
• Infectious Diseases

Background:

• Group 1 innate lymphoid cells (ILCs), including natural killer (NK) cells and ILC1s, modulate adaptive immunity.
• NK cells are known to eliminate activated T cells, influencing immune responses.

Purpose of the Study:

• To investigate the intrahepatic behavior and function of group 1 ILCs in mouse models of hepatitis B.
• To elucidate the cross-talk between group 1 ILCs and hepatitis B virus (HBV)-specific CD8+ T cells.

Main Methods:

• Multiphoton intravital microscopy in mouse models of hepatitis B.
• Analysis of group 1 ILC and CD8+ T cell interactions and proliferation.
• Assessment of IL-2 availability and its impact on T cell responses.

Main Results:

• Hepatocellular antigen recognition by CD8+ T cells increased hepatic NK cells and ILC1s.
• Group 1 ILCs interacted with CD8+ T cells but did not induce apoptosis.
• Group 1 ILCs constrained CD8+ T cell proliferation by limiting local IL-2 availability.

Conclusions:

• Group 1 ILCs play a crucial role in controlling T cell-mediated liver immunopathology.
• Limiting local IL-2 concentration is a key mechanism by which group 1 ILCs regulate T cell responses.
• These findings have implications for treating chronic HBV infection.