Feasibility of magnetic isolation CD133+ cells from human cord blood

by Alexey Bersenev on March 26, 2012 · 0 comments

in cell separation, cord blood

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CD133 is a “hot” stem cell marker, which currently is testing in clinical trials. But it seem like not easy to isolate CD133+ cells with consistency. The only method of cell isolation (based on surface markers) that allowed in clinic is a magnetic activated cell sorting (MACS). Last week I came across of report about some hurdles of isolation CD133+ cells from cord blood by MACS. The authors compared CD34+ versus CD133+ MACS and concluded:

CD34 isolation by the immunomagnetic method results in highly pure CD34+ population, while the efficient and reproducible yield of a pure CD133+ population is not feasible.

They used non-clinical miniMACS system and observed a great variation of CD133+ cell purity (10-85%) between samples. The purity of CD34+ cells was consistent (~ 93%). The authors have tried to improved CD133+ cell purity by different methods, but have observed the same result – the purity was low, inconsistent and non-reproducible.

Some interesting observations from the study:

No correlation was observed in the percentages between CD133 of the MNC fraction and those resulting from the immunomagnetic separation (yield ranged from 17.7% to 56.3%).

The variation in the purity of the CD133 population cannot be attributed to the different clones of CD133 used, because they do not cross-block, while other factors such as glycosylation, which could possibly interfere, do not apply in normal hematopoietic stem cells (HSC).

Despite standard manufacturer protocol (direct labeling), the authors used the following techniques to improve the purity:

  • extra labeling with CD133 microbeads
  • erythrocyte removal
  • indirect additional binding of the targeted surface antigen.

The author’s recommendations:

… it is recommended that the expression of CD133 antigen is assessed following each immunomagnetic isolation in the final selected CD133 population, in order to confirm the expected characteristics of the enriched population.

I wonder if you have any experience in isolating CD133+ cells by MACS. Please share with us here. It will be interesting to compare cord blood with bone marrow, miniMACS with CliniMACS.

Cytotherapy doi:10.3109/14653249.2012.663487

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