Serum-free media allows users to standardize their cell culture conditions by avoiding the use of undefined and highly variable serum products derived from humans or animals, e.g. human AB serum or fetal calf serum (FCS).

The high variability in the biological properties of different serum batches makes it necessary to pre-screen many batches in order to obtain a single one which is well suited for a given application. For example, even a brief exposure of PBMC (peripheral blood mononuclear cells) to a mitogenic serum batch during washing or freezing of these cells will result in a high background in cytokine assays, and toxic/inhibitory serum batches will jeopardize the assay results.  The unique performance of each serum batch necessitates the purchase of large lots to assure consistency of assay conditions as long as possible.  This adds to the inconvenience and cost associated with the use of serum.  Switching to, or using a different batch of serum introduces each time a significant unpredictable variable to the test conditions, making test results difficult to compare. 

For all these reasons, there is considerable pressure from regulatory agencies and from the scientific community to avoid the use of serum and move to consistent, defined substitutes.  However, because serum is naturally rich in a multitude of growth factors and other essentials of cell growth and functionality, it has been challenging to develop a serum substitute for primary cells in general, and for PBMC in particular.  Most serum free media are “rich enough” to permit the growth of robust tumor cells (e.g. hybridomas), but freshly isolated human PBMC require more stringent conditions to maintain their viability and activity in serum-free media. 

Cellular Technology Ltd. (CTL) has been working for years with the US Government, industrial- and academic partners to standardize ELISPOT and other direct ex vivo cytokine assays performed on freshly isolated and cryopreserved PBMC.  These efforts have resulted in CTL’s serum-free media platform. 

CTL’s serum-free platform consists of three product lines that have been carefully designed to cover the three critical steps of working with human PBMC: washing, testing and freezing.  All three previously required the use of serum.

Click here for CTL's Serum-Free Media Scientific Resource section