HLA homozygous stem cell lines derived from human parthenogenetic blastocysts

Area of Science:

• Stem Cell Biology
• Immunology
• Regenerative Medicine

Background:

• Human leukocyte antigen (HLA) matching is critical for successful cell-based therapies to avoid immune rejection.
• Parthenogenetic human stem cell (hpSC) lines offer potential for allogeneic transplantation but require HLA compatibility.
• Deriving HLA homozygous hpSC lines is essential for creating universally compatible cell therapies.

Purpose of the Study:

• To derive and characterize novel HLA homozygous parthenogenetic human stem cell (hpSC-Hhom) lines.
• To identify hpSC-Hhom lines with prevalent HLA haplotypes for broad clinical applicability.
• To assess the safety and genetic stability of derived hpSC-Hhom lines.

Main Methods:

• Derivation of hpSC lines from both HLA homozygous and heterozygous donors.
• Comprehensive characterization including morphology, stem cell marker expression, alkaline phosphatase, and telomerase activity assays.
• In vivo assessment via teratoma formation in immunodeficient animals, G-banded karyotyping, HLA genotyping, and single-nucleotide polymorphism (SNP) analysis.

Main Results:

• Successfully derived four stable hpSC-Hhom lines.
• hpSC-Hhom-4 line possesses the most common U.S. HLA haplotype, shared across racial groups.
• Derived lines exhibit typical embryonic stem cell characteristics, teratoma formation, and genetic stability (with noted anomalies in two lines).
• SNP analysis confirmed genome-wide homozygosity in lines from heterozygous donors.

Conclusions:

• Established HLA homozygous hpSC lines, including one with a highly prevalent HLA haplotype, suitable for potential clinical applications.
• The derivation protocol minimizes animal-derived components, enhancing clinical translation potential.
• These hpSC-Hhom lines represent a significant advancement towards HLA-matched, off-the-shelf cell therapies.