StemImmune FAQs

1. Is there a difference between humanized and bacterial proteins?

Yes. Recombinant human proteins require not only human gene coding sequences, but also post- transcriptional renaturation or modification processing, such as folding, phosphorylation, glycosylation, Etc., to become functional proteins, or only part of the biological activity. Only proteins expressed in human cells are similar to human native proteins.

2. ED50 and Units / mg between how conversion?

ED50 is defined as the half effective concentration, which is defined as the protein concentration that can induce a maximum response of 50%, which is only applicable to a dose response curve in the form of a S-shaped of the protein.
The formula for conversion of ED50 (ng / ml) to units / mg is as follows:


1x106/ ED50(ng/ml) = specific activity(units/mg)

3. What is StemImmune's protein stability? How to dilute and package?

StemImmune protein products are freeze-dried powder, can be sent at room temperature. However, it is recommended that you store it at -20 ° C to -80 ° C after receiving our products more appropriate to ensure that the protein 100% activity. The humanized protein, after resuspension, can only be stored for a short period of time (about 2-4 weeks) at 4 ° C. If you want long-term preservation, please first making dilution buffer, which must contain carrier protein, such as 0.1% HSA, is then stored frozen at -20 ° C or -80 ° C according to the experimental dose. Be sure to avoid repeat freezing and thawing, because each freeze-thaw can cause partial degradation of the protein. Small packaging of the protein will be affixed to the wall into a transparent membrane. Therefore, the proposed opening before the first fast centrifuge for 20-30 seconds to ensure that the protein is concentrated to the bottom of the tube and then re-opened with adding diluent, otherwise it will affect the amount of protein.

Different proteins with different dilutions:
The instructions must be read carefully before use. Such as: TGF and BMP series of proteins are diluted with acidic.

4. Is there cross-activity between proteins in different species?

Have. Most human cytokines are active in mouse cells and only a few cytokines are not active in murine cells. use. For example, human IL-7 is 60% homologous to murine, but its effect on mouse cells is stronger than the corresponding mouse cytokine activity.

5. Is there any difference between StemImmune's humanized protein and other companies' similar products?

Yes. StemImmune stabilized human cell lines selected by adaption were used as hosts for protein expression, and the purification process was stable without hashed buffer, so the small gap between the batches, good stability.

6. What is the concept of Animal Free and Xneo Free?

The StemImmune humanized protein uses a human cell expression system with a clear history of culture in serum free (such as calf serum) media. And the production follows a strict procedure, material with no animal contaminated material. If other expression systems are used, there will be some host protein contamination, it can’t be called non-source (Xeno Free) contamination protein.

7. Does StemImmune offer GMP-grade proteins and media?

Yes. StemImmune at any time according to customer requirements and the amount of GMP production. Both the protein and the medium StemImmune can be supplied as needed


Recombinant Human Activin A

Recombinant Human Activin A

Product Specifications Expression of Human Proteins in Human Cells Extreme low Endotoxin H..


Recombinant Human IL-7

Recombinant Human IL-7

Product Specifications Expression of Human Proteins in Human Cells Extreme low Endotoxin H..


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