5.1 Source materials and ancillary materials

5.1.1. The collection of human biological source material (source material) shall comply with the domestically recognized ethics and local laws and regulations.

5.1.2. Written and valid informed consent shall be signed by the donor. The content of informed consent shall include but not limited to the research purpose, potential research and clinical application under appropriate conditions feedback on unexpected discoveries potential commercial value and other issues affiliated to the research. Mechanisms for protecting the personal data and privacy of donors shall be established.

5.1.3. Organizations performed cell research and/or production shall establish and implement cell donor evaluation standards, and establish collection methods, transportation standards, handover standards and storage standards to ensure the safety of donors and cells. The source material shall be accompanied with detailed documentation on the acquisition methods and donor information, including but not limited to the donor's general information, past medical history and family history. The information of donor's blood type (e.g., ABO, Rh) and human leucocyte antigen (HLA) alleles should be documented as necessary.

5.1.4. The origin of cells shall be traceable by referring to the relevant informed consent and/or their genome and functional data.

5.1.5. Ancillary materials such as culture medium and growth factors shall meet the corresponding quality control requirements. The ancillary materials can be inspected and laboratory tested if necessary.

5.1.6. When using animal serum, they shall be free of contamination by viruses of animal origin. Serum from animals in geographical regions with prion epidemics (e.g., bovine spongiform encephalopathy) shall be prohibited.

5.1.7. If human blood components are used in the culture medium, including but not limited to albumin, transferrin and various cytokines, the source, batch number and quality verification reports shall be provided. State-approved products shall be used as much as possible.

5.1.8. The donors shall be screened for HIV, HBV, HCV, HTLV, EBV, HCMV and TP, and the results shall be documented.

5.2 Critical quality attributes 5.2.1 Cell morphology

Pigment can be seen in the cells. Under the condition of monolayer adherent growth, the cells are in close contact and polygonal.

5.2.2 Chromosome karyotype

The normal karyotype shall be 46, XY or 46, XX.

5.2.3 Cell survival rate

Shall be ≥90% before cryopreservation, and ≥50% post-thaw.

5.2.4 Cell marker protein

The expression of ZO-1 shall be ≥ 70% of the cell population. The expression of at least any three of the cell markers RPE 65, OTX2, MITF and BEST1 shall be ≥ 70% of the cell population.

5.2.5 Secretory function

Shall have the capacity of secreting PEDF and VEGF.

5.2.6 Microorganisms

Shall be negative for fungi, bacteria, mycoplasma, HIV, HBV, HCV, HTLV, HEBV, HCMV and TP.

5.3 Process control 5.3.1 Expansion

5.3.1.1. During the process of cell expansion, cross-contamination and mislabelling of cell lines shall be avoided, and risk mitigation measures shall be established.

5.3.1.2. During the process of cell expansion, the passage and the name of the cells shall be clearly specified, and the operation date, culture conditions, operators' names or initials shall be indicated.

5.3.2 Differentiation

5.3.2.1. During cell differentiation, the starter cells, equipment, culture conditions and operation procedures shall be defined and documented. The standard operating procedure for cell differentiation shall be established for reproducibility.

5.3.2.2. The differentiated cells from stem cells shall be clearly defined using characteristics, including but not limited to morphology, marker gene expression and functionality.

Note: This part is applicable for stem cell derived human retinal pigment epithelial cells.

5.3.3 Cryopreservation

5.3.3.1. Cryopreserved cells shall be clearly labelled with the cell line name, culture conditions, passage number, operator name and cryopreservation date. Cryopreserved cells shall have the same unique identification used during the process of harvesting, separation, expansion, etc.

5.3.3.2. The cryopreservation procedure shall follow the known principles of cryopreservation of mammalian cells and shall be recorded according to the relevant regulations.

5.3.4 Resuscitation

5.3.4.1. The resuscitation process shall be as rapid as possible to ensure the optimal viability and biological activity of cells.

5.3.4.2. Cell line information including but not limited to the cell line name, passage number, culture conditions, operator name or initials, resuscitation date and time shall be documented and recorded.

5.3.5 Cell STR identification

The STR signature of hRPEs shall be consistent with that of donor cells.