CD45 ligation expands Tregs by promoting interactions with DCs.

Area of Science:

• Immunology
• Cell Biology

Background:

• Regulatory T cells (Tregs) are crucial for immune tolerance.
• Current methods for Treg expansion are primarily ex vivo, limiting therapeutic applications.
• In vivo Treg expansion offers a more practical approach for therapeutic strategies.

Purpose of the Study:

• To investigate methods for in vivo expansion of Tregs.
• To determine if targeting CD45 can modulate Treg numbers and function.
• To elucidate the mechanisms by which CD45 ligation affects Treg-dendritic cell interactions.

Main Methods:

• Utilized a tolerogenic anti-CD45RB mAb in wild-type (WT) mice.
• Assessed Treg numbers and proliferation.
• Employed live imaging to observe Treg-dendritic cell interactions.
• Analyzed nuclear factor of activated T cells (NFAT) translocation.

Main Results:

• Administration of anti-CD45RB mAb led to acute increases in Treg numbers in vivo.
• Treg expansion was driven by augmented homeostatic proliferation and enhanced response to cognate antigen.
• CD45 ligation reduced Treg motility, increasing Treg-dendritic cell conjugation in an integrin-dependent manner.
• Enhanced Treg-dendritic cell interactions promoted NFAT translocation and Treg proliferation.

Conclusions:

• Targeting CD45 with anti-CD45RB mAb effectively promotes in vivo Treg expansion.
• Modulating Treg-dendritic cell interactions via CD45 ligation is a viable strategy for Treg-based therapies.
• This approach offers a novel method to enhance Treg peripheral homeostasis and promote immune tolerance.