PD-1 regulates KLRG1⁺ group 2 innate lymphoid cells

Area of Science:

• Immunology
• Cell Biology
• Infectious Disease

Background:

• Group 2 innate lymphoid cells (ILC-2s) are crucial for immune responses and tissue homeostasis.
• ICOS is a known positive regulator of ILC-2s.
• The role of PD-1 in ILC-2 regulation was previously unclear.

Purpose of the Study:

• To investigate the function of Programmed cell death protein 1 (PD-1) as a regulator of KLRG1+ ILC-2s.
• To determine the impact of PD-1 signaling on ILC-2 numbers and function in vivo.
• To explore the therapeutic potential of targeting PD-1 in parasitic infections.

Main Methods:

• Utilized knockout mouse models (Pdcd1-/-) to study PD-1 deficient ILC-2s.
• Employed adoptive transfer experiments with ILC-2s.
• Administered anti-PD-1 antibodies to assess in vivo effects.
• Analyzed STAT5 activation in ILC-2s.

Main Results:

• PD-1 acts as a negative regulator of KLRG1+ ILC-2 function in both mice and humans.
• PD-1 deficiency leads to increased KLRG1+ ILC-2 numbers due to enhanced STAT5 activation.
• Pdcd1-/- mice exhibited significant expansion of KLRG1+ ILC-2s during Nippostrongylus brasiliensis infection.
• Adoptive transfer of Pdcd1-/- ILC-2s reduced worm burden, and PD-1 blockade decreased disease severity.

Conclusions:

• PD-1 is essential for maintaining the appropriate number and function of KLRG1+ ILC-2s.
• Targeting PD-1 represents a potential therapeutic strategy for parasitic infections mediated by ILC-2s.