Qualified Mouse Embryonic Fibroblasts

Name: Primary MEFs (p0)

Code: MEF/001

Mouse Embryonic Fibroblasts (MEFs) are available to purchase from the NIBSC catalogue. You will need to have an account with NIBSC before ordering. You can apply for an account using the New Account Form.

Product description

Primary MEFs are used to support the growth of embryonic stem cells and induced pluripotent stem cells in the undifferentiated state. Primary MEFs supplied by the UK Stem Cell Bank have been qualified for this purpose.

UK Stem Cell Bank Primary MEFs have been shown, up to passage 5 (PDL10), to support the undifferentiated growth and proliferation of a range of human embryonic stem cells as part of our qualification programme.

Primary MEFs are dissociated from day 13.5 MF-1 mouse embryos, expanded then cryopreserved as frozen primary cells. Each 2 mL cryovial contains approximately 106 cells in 1 mL of DMEM containing 10% foetal bovine serum and 10% dimethyl sulphoxide. All vials are stored in the vapour phase of LN2 below -160°C.


One vial of Primary MEFs, if cultured according to the UK Stem Cell Bank protocol supplied with the cells, will produce the equivalent of at least twenty 6-well plates at passage level 3 or one hundred and twenty 6-well plates at passage level 5. The cells must be mitotically inactivated by irradiation or mitomycin C treatment prior to co-culture with ESCs or iPSC for optimum maintenance of the undifferentiated pluripotent cells.

Quality control

All UK Stem Cell Bank cell products are tested for viability, sterility and mycoplasma. Qualified MEFs are produced from out-bred SPF mice tested for a number of murine viruses. The Primary MEFs are cultured in media containing irradiated FBS from certified BSE-free herds and batch tested for bovine viruses including BVD-V. Mouse Colony Health Certificates and Certificate of Analysis are available on requestPrimary MEFs are tested for stem cell supportiveness against a range of ESCs including H9 and are used routinely within the UK Stem Cell Bank. A Certificate of Analysis is provided with each order.

Handling and storage

For complete instructions on how to culture p0 MEFs please contact the UK Stem Cell Bank at enquiriesmail@mhra.gov.uk. All procedures should be carried out using aseptic technique in a certified Class II biological safety cabinet. Cells should be stored on receipt at -135°C or colder, or in liquid nitrogen.