Conditioned medium is spent media harvested from cultured cells. It contains metabolites, growth factors, and extracellular matrix proteins secreted into the medium by the cultured cells. Examples of each might include: metabolites such as glucose, amino acids, and nucleosides; growth factors such as interleukins, EGF (epidermal growth factor), and PDGF (platelet-derived growth factor); and matrix proteins such as collagen, fibronectin, and various proteoglycans. Most cell lines requiring conditioned medium are dependent on at least one major constituent found in the conditioned medium
For example, one of the major growth factors present in LADMAC conditioned medium is CSF-1 (colony stimulating factor 1). CSF-1 assists with macrophage progenitor proliferation and differentiation. LADMAC conditioned medium is obtained from the LADMAC cell line ATCC® CRL-2420 ™ and is added to the growth media used to propagate ATCC® CRL-2467 ™, ATCC® CRL-2468 ™, ATCC® CRL-2470™, and ATCC® CRL-2471™, all of which express colony stimulating factor 1 receptors.
Mouse embryonic stem cells (ESC) also benefit from growth-promoting components found in conditioned medium. LIF (leukemia inhibitory factor) is secreted into medium by near-primary cultures of mouse embryonic fibroblasts (MEF), and is an essential component in maintaining the undifferentiated state of ESCs. For example, ATCC® SCRC-1002 ™ requires both the use of a mouse embryonic fibroblast feeder layer, as well as additional supplementation with purified LIF (Chemicon, ESG1107) to maintain the undifferentiated state of the embryonic stem cells.
It is important to bear in mind that omission of conditioned medium from a cell line requiring this type of supplementation should be carefully evaluated. While most cell lines are, in fact, dependent on at least one major constituent found in the conditioned medium, replacing the conditioned medium with a recombinant, or purified, form of this one, single growth factor may yield unfavorable results such as altered expression phenotypes, slowed growth, quiescence or even complete loss of the culture. Any of these responses would indicate that the conditioned medium contains more than just a single growth factor essential to the healthy maintenance and growth of the cells.
References: Freshney RI. Culture of Animal Cells: A Manual of Basic Technique, 5th ed. New York: Wiley Liss; 2005.
|Date Created||07/17/2012 07:11 PM
|Date Updated||02/02/2013 01:12 PM