Integrate CRISPR/Cas9 for protein expression of HLA-B*38:68Q via precise gene editing

Sci Rep. 2019 May 30;9(1):8067. doi: 10.1038/s41598-019-44336-7.

Abstract

The determination of null- or low-expressed HLA alleles is clinically relevant in both hematopoietic stem cell transplantation and solid organ transplantation. We studied the expression level of a questionable (Q) HLA-B*38:68Q allele, which carries a 9-nucleotide (nt) deletion at codon 230-232 in exon 4 of HLA-B*38:01:01:01 using CRISPR/Cas9 gene editing technology. CRISPR/Cas9 gene editing of HLA-B*38:01:01:01 homozygous EBV B cell line resulted in one HLA-B*38:68Q/B*38:01:01:01 heterozygous and one HLA-B*38:68Q homozygous clone. Flow cytometric analysis of monoclonal anti-Bw4 antibody showed the protein expression of HLA-B*38:01:01:01 in homozygous cells was 2.2 fold higher than HLA-B*38:68Q/B*38:01:01:01 heterozygous cells, and the expression of HLA-B*38:68Q/B*38:01:01:01 heterozygous cells was over 2.0 fold higher than HLA-B*38:68Q homozygous cells. The HLA-B*38:68Q expression was further confirmed using anti-B38 polyclonal antibody. Similarly, the expression of the HLA-B*38:01:01:01 homozygous cells was 1.5 fold higher than that of HLA-B*38:68Q/B*38:01:01:01 heterozygous cells, and the HLA-B*38:68Q/B*38:01:01:01 heterozygous cells was over 1.6 fold higher than that of HLA-B*38:68Q homozygous cells. The treatment of HLA-B*38:68Q homozygous cells with IFN-γ significantly increased its expression. In conclusion, we demonstrate that HLA-B*38:68Q is a low-expressing HLA allele. The CRISPR/Cas9 technology is a useful tool to induce precise gene editing in HLA genes to enable the characterization of HLA gene variants on expression and function.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Alleles
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism
  • CRISPR-Cas Systems / genetics*
  • Cell Line
  • Exons / genetics
  • Feasibility Studies
  • Gene Editing / methods*
  • Gene Expression Regulation / genetics
  • Gene Expression Regulation / immunology
  • HLA-B38 Antigen / genetics*
  • HLA-B38 Antigen / immunology
  • HLA-B38 Antigen / metabolism
  • Herpesvirus 4, Human / genetics
  • Heterozygote
  • Histocompatibility Testing / methods*
  • Homozygote
  • Humans
  • Polymorphism, Genetic / immunology
  • Sequence Deletion
  • Transfection

Substances

  • HLA-B38 Antigen