Technical library

For optimal cell performance, we generally recommend culturing cells without antibiotics whenever possible. However, if the use of antibiotics is deemed necessary, please use the following final concentrations:
Penicillin: 100 U/ml + Streptomycin: 100 µg/ml
or
Gentamicin: 50 µg/ml + Amphotericin B: 50 ng/ml
 
Important note
The addition of antibiotics may reduce the growth rate of cells and can mask low‑level contamination. Antibiotics should therefore be used with caution, but may be helpful in situations where maintaining contamination‑free cultures is particularly challenging.

PromoCell human renal epithelial cells (HREpC and HRCEpC) are characterized based on their epithelial phenotype.
 
Characterization criteria

• Typical epithelial cell morphology
• Expression of cytokeratins, confirmed by immunostaining using a pan‑cytokeratin antibody

This combination of morphological assessment and marker expression confirms the epithelial identity of the kidney cell cultures.

The difference between PromoCell HREpC and HRCEpC lies in the anatomical origin of the cells:

• HREpC (C‑12665) comprise a heterogeneous population of renal epithelial cells isolated from both the renal cortex and the renal medulla.
• HRCEpC (C‑12660) are exclusively derived from the renal cortex.

As a result, HREpC represent a broader mix of renal epithelial subtypes, while HRCEpC are restricted to cortex‑derived epithelial cells.

A common reason for a lower cell yield with M2 Macrophage Generation Medium compared to M1 Macrophage Generation Medium is that the shelf life of the M2 medium has been exceeded after cytokine supplementation.
For M2 Macrophage Generation Medium, it is critical that the supplemented medium is used within 2 weeks after addition of the cytokines. Beyond this time frame, the activity of the cytokines decreases, which can rapidly lead to a reduced differentiation efficiency and lower macrophage yield.
To ensure comparable results between M1 and M2 macrophage cultures, it is therefore strongly recommended to use the M2 medium as fresh as possible.

Most PromoCell subcutaneous Human White Preadipocyte (HWP) lots achieve a differentiation ratio of > 80-90% when adipogenic differentiation is induced at passage 2 (P2), directly after thawing.
For optimal differentiation performance, PromoCell recommends:

• using cells that have undergone no more than 4-5 population doublings, and
• performing differentiation without exceeding one passage after thawing.

As preadipocytes age in culture, their differentiation capacity gradually declines, resulting in lower differentiation ratios.

No. We do not recommend shortening the centrifugation time.
Centrifugation at 350×g for 15 minutes has been validated and tested by PromoCell and is also used during quality control testing.
Reducing the centrifugation time or g‑force may result in significant cell loss, as intact macrophages may not sediment completely.

Recommendation
To ensure reliable recovery of macrophages for flow cytometric analysis, please follow the validated centrifugation conditions of 15 minutes at 350×g.

Yes, this observation is normal and does not indicate true cell attachment.
CD34⁺ progenitor cells cultured in HPC Expansion Medium XF (C‑28021) are non‑adherent cells. During culture, they may sink to the bottom of the culture vessel, which can give the impression that they have attached.
However:

• The cells do not firmly attach to the tissue culture plastic
• They retain a round morphology
• They can be easily rinsed off with culture medium

PromoCell human blood cells are cryopreserved directly after isolation, corresponding to passage 0 (P0).

• The cells have not been cultured prior to freezing.
• They therefore arrive without any in vitro expansion history.

No. Hematopoietic progenitor cells (e.g. CD34⁺ or CD133⁺ cells) will not proliferate in Hematopoietic Progenitor Cell Expansion Medium XF (C‑28021) without additional cytokines.
 
Required supplementation
For efficient expansion, the medium must be supplemented with either:

• Cytokine Mix E (C‑39890), or
• a user‑defined cytokine mixture with equivalent functionality.

Cytokine Mix E is a ready‑to‑use formulation containing recombinant human Thrombopoietin (TPO), Stem Cell Factor (SCF), Flt3‑Ligand, and Interleukin‑3 (IL‑3).
 
Expansion performance
When used in combination with Cytokine Mix E, Hematopoietic Progenitor Cell Expansion Medium XF supports strong progenitor cell expansion for at least two weeks.

All PromoCell Adult Human Stem and Blood Cells are phenotypically characterized by flow cytometry to confirm the expression of defined, cell‑type‑specific surface markers.
 
Additional characterization of MSCs
In addition to marker analysis, Mesenchymal Stem Cells (MSCs) are functionally tested for their ability to differentiate into the three mesenchymal lineages:

• osteogenic
• chondrogenic
• adipogenic

Where to find the details
The exact markers tested for each cell type are listed in the Certificate of Analysis (CoA) of the respective product.