Modulation of γδ T-cell activation by neutrophil elastase

Area of Science:

• Immunology
• Cell Biology

Background:

• Gamma delta (γδ) T cells are innate-like lymphocytes with a unique T-cell receptor repertoire.
• They play critical roles in pathogen defense, tumor surveillance, and tissue homeostasis.

Purpose of the Study:

• To investigate the role of neutrophils in the activation of human blood γδ T cells.
• To elucidate the molecular mechanisms underlying neutrophil-mediated potentiation of γδ T cell responses.

Main Methods:

• Human blood γδ T cells were activated using anti-CD3 antibodies.
• The influence of neutrophils on γδ T cell activation markers (CD69) and cytokine production (IFN-γ, TNF-α) was assessed.
• Caspase-1 inhibition, IL-18 neutralization, serine protease inhibitors, elastase, and PAR1 antagonists were employed to dissect the mechanisms.

Main Results:

• Neutrophils significantly potentiated anti-CD3-induced CD69 expression and cytokine production by γδ T cells.
• Neutrophil-mediated potentiation was independent of caspase-1 and IL-18.
• Serine protease activity, specifically neutrophil elastase, was crucial for this potentiation.
• Elastase-induced γδ T cell activation was mediated via the protease-activated receptor 1 (PAR1).

Conclusions:

• Neutrophils enhance γδ T cell activation through the release of serine proteases, particularly elastase.
• Elastase acts on γδ T cells via PAR1, leading to increased stimulation.
• These findings reveal a novel mechanism of innate-like immune cell cross-talk with implications for immune responses.