Generation of hypoimmunogenic human pluripotent stem cells

Area of Science:

• Immunology
• Stem Cell Biology
• Genetic Engineering

Background:

• Polymorphic human leukocyte antigens (HLAs) are a major barrier to successful cell therapy.
• Both adaptive and innate immune responses contribute to the rejection of transplanted cells.
• Current strategies lack the ability to simultaneously address both adaptive and innate immunity.

Purpose of the Study:

• To develop a universal cell therapy approach by engineering human pluripotent stem cells.
• To overcome immune rejection by targeting both adaptive and innate immune surveillance pathways.
• To enhance cell engraftment and therapeutic efficacy for broader clinical application.

Main Methods:

• Multiplex genome editing was used to ablate HLA class I (HLA-A/-B/-C) and HLA class II expression.
• Immunomodulatory factors (PD-L1, HLA-G) and a "don't-eat me" signal (CD47) were expressed from the AAVS1 safe harbor locus.
• In vitro and in vivo immunoassays were performed to assess immune responses.

Main Results:

• Engineered stem cells demonstrated blunted T cell responses.
• Natural killer (NK) cell-mediated killing of engineered cells was significantly reduced.
• Macrophage engulfment of the engineered cells was minimal, indicating evasion of innate immunity.
• The approach effectively suppressed both adaptive and innate immune responses.

Conclusions:

• This strategy provides a method to simultaneously control adaptive and innate immunity against cell therapies.
• The engineered cells show potential for broader application in cell therapy by overcoming immune barriers.
• This approach may significantly advance the clinical translation of cell-based therapeutics.