Trial using pig cells with the H-D antigen knocked down

Area of Science:

• Xenotransplantation research
• Immunology
• Molecular biology

Background:

• Hanganutziu-Deicher (H-D) antigens are key targets in xenotransplantation.
• Reducing H-D antigen expression is crucial for mitigating hyperacute rejection.
• Pig cytidine monophospho-N-acetylneuraminic acid hydroxylase (pCMAH) is responsible for H-D antigen synthesis.

Purpose of the Study:

• To investigate the efficacy of small interfering RNA (siRNA) in reducing pCMAH expression.
• To assess the impact of pCMAH silencing on H-D antigen levels and antigenicity.
• To evaluate the reduction in xenoantigenicity against human serum.

Main Methods:

• Utilized pig endothelial cell (PEC) lines and fibroblasts, including GalT-KO cells.
• Employed real-time PCR to confirm mRNA degradation by siRNA.
• Assessed H-D antigen expression via staining and FACS analysis.
• Quantified cell lysis using LDH assay after incubation with human serum.

Main Results:

• siRNA effectively suppressed pCMAH mRNA expression.
• Reduced H-D antigen expression on both PEC and fibroblasts.
• Demonstrated a significant decrease in xenoantigenicity in GalT-KO cells.
• Observed a notable downregulation of complement-dependent cytotoxicity in PEC lines.

Conclusions:

• pCMAH silencing via siRNA is a viable strategy to reduce H-D antigen expression.
• This approach diminishes the antigenicity of pig cells, decreasing hyperacute rejection risk.
• H-D antigen is confirmed as a major non-Gal antigen contributing to xenograft rejection.