Commentary on differential impact of TIM-3 ligands on NK cell function

Area of Science:

• Immunology
• Cancer Biology
• Molecular Biology

Background:

• T-cell immunoglobulin and mucin-domain containing molecule 3 (TIM-3) is an immune checkpoint receptor targeted by immune checkpoint blockers (ICBs).
• The clinical success rate of anti-TIM-3 ICBs is limited in human patients.
• TIM-3 expression on multiple immune cells affects their function through ligand interactions.

Purpose of the Study:

• To investigate which TIM-3 ligands impair natural killer (NK) cell cytotoxicity and proliferation.
• To explore the role of TIM-3 and NK cells in head and neck squamous cell carcinoma (HNSCC) survival.

Main Methods:

• Investigated interactions between TIM-3 ligands (HMGB1, galectin-9, phosphatidylserine, CEACAM1) and NK cells.
• Assessed the impact of these interactions on NK cell cytotoxicity and proliferation.
• Analyzed TIM-3 and NK cell transcriptional signatures in HNSCC patient data.

Main Results:

• Galectin-9 inhibited NK cell cytotoxicity in a TIM-3-dependent manner.
• Galectin-9 blocked NK cell proliferation via interaction with CD44 on NK cells.
• A high TIM-3+NK cell signature correlated with poor survival in HPV-associated HNSCC.

Conclusions:

• Understanding TIM-3 ligand interactions with NK cells is crucial for improving ICB efficacy.
• Galectin-9's inhibitory effect on NK cells may explain limited anti-TIM-3 monotherapy success.
• Findings suggest combination strategies and patient selection based on TIM-3/NK cell status for HNSCC treatment.