We recently finished our Ask the Expert discussion on optimization of serum free media for the propagation of primary and stem cells in animal and human serum component free conditions. During this Ask the Expert session, we discussed optimizing primary and stem cell culture to reduce or remove serum. Topics covered included resolving variability issues, reducing versus eliminating serum, media screening, animal free vs. serum free ad coating matrix.

Optimization of serum free media can be a complex and daunting challenge for scientists working to bring a cellular therapy to market. When considering raw material sourcing, it is important to limit animal or human serum derived components as these are major sources of variability and potential viral contamination risks. Inclusion of recombinant versions represents a viable alternative to circumvent issues associated with serum-derived proteins. However, utilization of these components can sometimes bring new hurdles to light.

This Ask the Expert session was sponsored by InVitria and is hosted by Randall Alfano. Mr. Alfano, Cell Culture Scientist, joined InVitria in 2012. He currently develops animal free proteins and supplements for various cell systems including stem cells. He has over  6 years’ experience in recombinant protein expression and purification as well as medium development for CHO-based biomanufacturing and stem cells. Randall was awarded his Ph.D. in 2009 from the Texas A&M College of Medicine Health Science Center in Cell Biology.

Below is a sneak peek of the discussion, for a full transcript, please see – Ask the Expert – optimization of serum free media for the propagation of primary and stem cells in animal and human serum component free conditions.

Question:

I am working on reducing serum in our iPCS culture. What steps would you recommend for weaning and in your experience how low have you gotten in serum concentration?

The Answer:

I would highly recommend a step wise reduction in serum for iPSC over multiple passages. There are a variety of serum free medias currently marketed for iPSCs, so these cells can be propagated in serum free conditions. In addition, we have developed in house animal component free formulations that are capable of expanding iPSC for at least 12 passages while retaining all of the desired phenotypic traits. When combined with a recombinant vitronectin matrix, these cells can be expanded in media that is completely void of any human or animal serum components. If you are interested in formulations such as these, we can further discuss

Question:

In your opinion if you have determined that you can’t get rid of serum completely is there any advantage (beyond cost) to trying to reduce it?

The Answer:

Total elimination of serum versus serum reduction will be determined by the end application of the cell-based product. For therapeutic applications, it is best to totally eliminate serum for variability and safety reasons. If you find that you are having difficulty in removing serum completely, I would be interested in talking with you further to see if we can solve your issue. Simply reducing serum in a medium is a viable alternative if the end use allows (i.e. R&D). There are a few advantages to having a reduced serum medium versus a serum free medium. Namely, it is generally well known that cells cultured in serum are more durable and can withstand environmental insults (i.e. temperature and pH shifts during handling) slightly better than when cultured in serum free media.

Question:

I am currently culturing MSCs with platelet lysate, do you think there is reason to switch to completely animal free or is avoiding serum enough?

The Answer:

Human platelet isolate has been considered to be an alternative to serum in the expansion of MSC. Although platelet isolate is free of bovine components, there is still risk of viral contamination since this is derived from human serum. In addition, this material can vary from lot to lot which warrants the qualification of a lot prior to the incorporation into a manufacturing process.