Dear Maria,

Please answer these questions to clarify the issue:

1- What kind of stem cells you want to isolate from fibroblasts?

Different stem cell have different surface markers. For example pluripotent ones (including iPS and embryonic stem cells) express SSEA-4 and Tra1-60 in their surfaces while mesenchymal stem cells express some CD markers like CD70, CD105 and so on.

2- Are you trying to separate pluripotent stem cells from fibroblast based feeder layer (like MEF)??

3- A highlighted surface marker for fibroblasts is CD90 (Thy1). But unfortunately it is also expressed in mesenchymal stem cells so it is not possible to separate MSCs and fibroblast by targeting this CD marker. But if you want to isolate pluripotent ones from fibroblasts, it will be useful.

4- please describe any useful details which can help us to understand the problem.

Dear Alireza Naderi Sohi,

Thank you for explanation, basically I want to recognize a side population of stem cells (embryonic stem cells) in culture of Human pulmonary fibroblasts by flow cytometry. There are no separation or any other manipulation on these cells.

Dear Maria,

As Alireza Naderi Sohi already explained, you should go forward with a TRA-1-60 and/or SSEA4 FACS experiment. We are using those two markers (as double labelling) to characterize our iPSC lines. We use the TRA-1-60-PE and SSEA4-APC FACS antibodies (together with the Viobility Fiaxble Dyes for live/dead discrimination and matching REA-isotype controls) from Miltenyi Biotec (no affiliation) and never had any problems with them (e.g. unspecific staining).

https://www.miltenyibiotec.com/DE-en/products/macs-flow-cytometry/antibodies/primary-antibodies/anti-tra-1-60-antibodies-human-rea157-1-11.html#pe:for-30-tests

Best,

Thomas