Questions and Answers
Q: What is Cellastim?
A: Cellastim™ is cell culture grade recombinant human Serum Albumin
(HSA) that has been produced from an animal-free expression system1. Cellastim
is animal-free and immunoglobulin free. Cellastim has identical amino
acid sequence (585 amino acids, 66.5kDa) and similar biophysical properties
compared to the major HSA isoform found in human serum. Albumin is a component
of serum that functions as a carrier protein for fatty acids, growth factors,
and trace minerals. Albumin also protects cells from damage from toxins
and physical shear. Albumin is a common ingredient in many classical and
custom media formulations2.
Q: What are the primary uses of Cellastim in cell culture?
A: Primary uses of Cellastim in media are to reduce or eliminate the
use of serum or animal-derive albumin in media formulations and to support
cell growth, productivity, and health.
Q: What are the advantages of using Cellastim in cell culture?
A: Cellastim is animal-free and immunoglobulin-free albumin for use in
media formulations. Albumin in media formulations can enhance the growth
or productivity of cells grown in serum-free or reduced-serum media. The
effects of albumin on growth and productivity are well documented, but
poorly understood mechanistically but are cell line and media dependent.
In addition, albumin has been reported to protect cells from physical
damage in stirred culture, protect cells from oxidative damage, and to
support the absorption of nutrients in media.
Q: How much Cellastim is effective in media?
A: The optimum concentration of Cellastim for cell culture varies with
the cell line and media composition. Many classical media formulation
include albumin at concentration between 0.5 and 1 g/L3. Cellastim can
be used as a media supplement at concentrations up to 2 g/L.
Q: Do cell lines require adaptation to Cellastim?
A: Cell lines previously adapted to growth in serum-free formulations
generally require little or no adaptation to grow in the same medium supplemented
with Cellastim. However, we recommend gradual adaptation over several
passages with 0.5 to 1g/L as an initial use. Cell lines adapting to serum-free
medium from serum-supplemented medium may require an additional adaptation
period. Following adaptation, we recommend the end user optimize effective
Cellastim concentration for their particular purpose.
Q: Does Cellastim function equivalently to plasma derived Albumin?
A: Our evaluation is ongoing. Results generated to date indicate that
Cellastim functions similar to or better than plasma-derived HSA in stimulating
cell growth and productivity in serum free-media at concentrations up
to 2 g/L.
Q: Is Cellastim approved for direct therapeutic use in humans?
A: No. Cellastim is cell culture grade recombinant HSA. Cellastim is
not approved for direct therapeutic use in humans.
Q: How should I prepare solutions of Cellastim?
A: We recommend dissolving Cellastim in a buffered salt solution, Dulbecco’s
PBS, or directly into media. Gentle mixing on a rotary shaker for a few
minutes is helpful. Following preparation, Cellastim solutions can be
sterile filtered through a .45µ or 0.2µ pore-size filter.
To filter Cellastim solutions below 0.2µ we recommend prefiltering
at 0.45µ or larger pore-size.
References:
1. Nandi, S. et al. Transgenic Research. 14:237-249 (2005).
2. Focus on Alternatives, Serum-Free Media for Cell Culture, (July 2005).
3. Chua, F, et al. J. Immunol. Methods. 167:109-119 (1994).
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