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

Recent advances in stem cells and gene editing: Drug discovery and therapeutics

The recently introduced genome editing technology has had a remarkable impact on genetic medicine. Zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR)/Cas nucleases are the three major platforms used for priming of stem cells or correction of mutated genes. Among these nucleases, CRISPR/Cas is the most easily applicable. Various CRISPR/Cas variants such as base editors, prime editors, mad7 nucleases, RESCUE, REPAIR, digenome sequencing, and SHERLOCK are being developed and considered as a promising tool for gene therapy and drug discovery. These advances in the CRISPR/Cas platform have enabled the correction of gene mutations from DNA to RNA level and validation of the safety of genome editing performance at a very precise level by allowing the detection of one base-pair mismatch. These promising alternatives of the CRISPR/Cas system can benefit millions of patients with intractable diseases. Although the therapeutic effects of stem cells have been confirmed in a wide range of disease models, their safety still remains an issue. Hence, scientists are concentrating on generating functionally improved stem cells by using programmable nucleases such as CRISPR. Therefore, in this chapter, we have summarized the applicable options of the CRISPR/Cas platforms by weighing their advantages and limitations in drug discovery and gene therapy.

New directions in chimeric antigen receptor T cell [CAR-T] therapy and related flow cytometry

Chimeric antigen receptor (CAR) T cells provide a promising approach to the treatment of hematologic malignancies and solid tumors. Flow cytometry is a powerful analytical modality, which plays an expanding role in all stages of CAR T therapy, from lymphocyte collection, to CAR T cell manufacturing, to in vivo monitoring of the infused cells and evaluation of their function in the tumor environment. Therefore, a thorough understanding of the new directions is important for designing and implementing CAR T-related flow cytometry assays in the clinical and investigational settings. However, the speed of new discoveries and the multitude of clinical and preclinical trials make it challenging to keep up to date in this complex field. In this review, we summarize the current state of CAR T therapy, highlight the areas of emergent research, discuss applications of flow cytometry in modern cell therapy, and touch upon several considerations particular to CAR detection and assessing the effectiveness of CAR T therapy.

Expression profile of HLA-B*38:55Q allele

The identification of null or questionably expressed HLA allelic variants is a major issue in HLA diagnostics, because the mistyping of the aberrant expression of such alleles can have a major impact on the outcome of both hematopoietic stem cell transplantation (HSCT) and solid organ transplants. It is debated how questionable (Q) alleles, because of their unknown expression profile, should be considered in an allogenic HSCT setting. The HLA-B*38:55Q allele was detected as an HLA-B blank specificity; DNA sequencing identified a single polymorphism at position 373 in exon 3 (TGC > CGC), which results in the replacement of cysteine 101 with an arginine in the HLA-B heavy chain, thus, impairing disulfide bridge formation in the alpha-2 domain, essential for the normal expression of the HLA molecules. In order to determine the RNA and protein expression profile of this allelic variant, we analyzed antigenic expression at different levels, transcriptional and transductional, using a combination of cellular methods, such as serological testing and flow cytometric analysis, polymerase chain reaction (PCR) sequence-specific primer (SSP) cDNA group-specific amplification and immunocytochemical assay, demonstrating the prevalent cytoplasmatic distribution of the HLA-B*38:55Q protein. Our findings suggest that in matching process the HLA-B*38:55Q allele needs to be considered as a low expressed allele, able to elicit an allogenic T-cell response in vivo and impair the transplant outcome.