Galectin-1 binds different CD43 glycoforms to cluster CD43 and regulate T cell death

Area of Science:

• Immunology
• Glycobiology
• Cell Biology

Background:

• Galectin-1 induces T cell death by binding to cell surface glycans.
• While CD7 and CD45 roles are known, CD43's role in galectin-1-induced T cell death is unclear.
• CD43 is a heavily O-glycosylated T cell surface protein.

Purpose of the Study:

• To investigate the role of CD43 in galectin-1-induced T cell death.
• To examine how O-glycan modification on CD43 affects galectin-1 binding.

Main Methods:

• Assessed galectin-1-induced cell death in murine thymocytes and human T lymphoblastoid cells with and without CD43.
• Quantified galectin-1 binding to T cells expressing or lacking CD43.
• Analyzed galectin-1 binding to CD43 fusion proteins with different O-glycan modifications (core 1 and core 2).

Main Results:

• Loss of CD43 significantly reduced galectin-1-induced death in T cells.
• T cells lacking CD43 showed approximately 50% less galectin-1 binding.
• Galectin-1 bound to CD43 irrespective of core 1 or core 2 O-glycan structures and induced CD43 clustering.

Conclusions:

• CD43 plays a crucial role in mediating galectin-1-induced T cell death.
• CD43, with either core 1 or core 2 O-glycans, enhances T cell susceptibility to galectin-1.
• Different T cell glycoproteins have distinct glycan requirements for galectin-1 interaction.