Human Leukocyte Antigen (HLA) is the human major histocompatibility complex (MHC), located on the short arm of chromosome 6 (6p21.31), composed of 3.6 million base pairs, including a series of closely linked loci. The gene loci are closely related to the function of the human immune system. These genes encode cell surface antigens and become an inconspicuous "feature" of each person's cells. They are the basis for the human immune system to distinguish between "autologous" and "exogenous" substances. The specificity of HLA in different individuals is also the main reason for rejection in allogeneic organ transplantation or cell therapy. Exactly, the same HLA matching results are the most ideal transplant donors. However, there are currently more than 14,000 HLA alleles reported by the WHO worldwide, and there are many possibilities for arrangement and combination. However, due to the existence of "linkage disequilibrium", certain genes tend to be grouped together instead of completely random combination. Therefore, there is such a special individual. They are homozygous with common HLA haplotypes. The HLA genotypes of such special individuals can match a higher proportion of people.
iPSC makes it possible to prepare patients' own pluripotent stem cells. Cell therapy based on the production of human functional cells needed by the patient's own IPSC can avoid or reduce immune rejection to the greatest extent. However, due to time and cost constraints, it is impractical to prepare an autologous iPSC for each patient for cell medicine, and the production and quality control processes are also difficult to manage. Therefore, in order to allow more patients to enjoy the benefits of cell medicine, we need to prepare iPSC that match the HLA of the Chinese population.
Nuwacell Biotechnologies Co., Ltd. has been committed to the construction of a super donor's stem cell bank for the Chinese population, and uses these seed cells to develop universal cellular drugs for the general public. By studying the distribution of HLA matching in a large population, Nuwacell Biotechnologies Co., Ltd. plan screened the top 200 high-frequency HLA homozygous genotypes with the highest coverage, and prepared iPSC according to the requirements of clinical-grade cells.
Since the successful preparation of the first super-donor's iPSC for the Chinese population in September 2018, Nuwacell Biotechnologies Co., Ltd. has successively successfully prepared and stored 30 super-donor iPSC, which can cover about 20% of the national population, that is, 300 million Chinese people. We also established a standardized plan and quality control standards for the preparation of clinical-grade hiPSC. In the future, Nuwacell Biotechnologies Co., Ltd. will continue to look for super donors for the Chinese population and establish an other iPSC cell bank covering most Chinese populations.