CD47 Enhances In Vivo Functionality of Artificial Antigen-Presenting Cells

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Artificial antigen-presenting cells (aAPCs) are effective for stimulating T-cell responses in vitro and in vivo.
• In vivo, aAPCs can be rapidly cleared by macrophages, limiting their therapeutic potential.
• Strategies to prevent macrophage uptake are needed to enhance aAPC efficacy.

Purpose of the Study:

• To investigate the efficiency of "don't eat me" three-signal aAPCs (aAPC(CD47+)) compared to classical two-signal aAPCs.
• To determine if CD47 immobilization on aAPCs can prevent macrophage clearance and improve in vivo functionality.

Main Methods:

• Generated "don't eat me" aAPCs by immobilizing CD47 onto classical aAPCs (aAPC(CD47+)).
• Analyzed aAPC and aAPC(CD47+) in in vitro human T-cell and macrophage co-cultures.
• Compared in vivo efficiency in a NOD/SCID T-cell proliferation model and a B16-SIY melanoma model.

Main Results:

• aAPC(CD47+) demonstrated CD47 concentration-dependent inhibition of phagocytosis by macrophages in vitro without affecting T-cell stimulation.
• T cells generated by aAPC(CD47+) exhibited equivalent killing abilities and polyfunctionality compared to those generated by classical aAPCs.
• In vivo studies showed enhanced stimulatory capacity and tumor inhibition with aAPC(CD47+) compared to normal aAPCs, with altered biodistribution.

Conclusions:

• CD47-functionalized aAPCs (aAPC(CD47+)) maintain in vitro stimulatory capacity while enhancing in vivo efficiency.
• These next-generation aAPC(CD47+) show significant potential for improving aAPC technology in immunotherapy.
• The findings support the development of aAPC(CD47+) as a promising strategy for enhanced cancer immunotherapy.