solubilized and added by the customer only shortly before the start of the culti-

vation. Moreover, some media are very fragile to degradation by light. Hence,

containers used for storage should be light-protected. For CHO cells, many media

supporting efficient growth and high-product yields are available today. This is in

strong contrast to media available for many cell lines used in vaccine production.

For the latter, there is still much room for optimization. This concerns not only

growth properties but also metabolic pathways, which modulate virus production.

Many effects of media supplementation have been identified including changes in

lipid-, energy-, nucleic acid-, oxidative stress-, and polyamine metabolism, protein

processing and post-translational modification as well as control of cell cycle and

apoptosis. For instance, an increase in infectious virus titers of up to sixfold through

additions of various supplements has been reported by Rodrigues et al. [37].

Media formulation is additionally constrained to osmolality. The osmolality of

the medium refers to “the concentration of osmotically active particles in that so-

lution” [40]. Human blood plasma has an osmolality of approximately 290

mOsmol/kg. To mimic physiological conditions, cell culture media are adjusted to

values of 260–330 mOsmol/kg. However, most continuously growing mammalian

cells can show a very wide tolerance up to 500 mOsmol/kg [41]. Yet, cells will

react to the respective osmolality of the medium by either shrinking (hyperosmotic,

>330 mOsmol/kg) or swelling (hypoosmotic, <260 mOsmol/kg). During the cul-

tivation, osmolality is changed by addition of salts, release of metabolites (lactate),

feeding, and addition of buffers. Furthermore, monitoring of the osmolality can be

TABLE 5.4 (Continued)

Specific media components, typical concentrations, characteristics,

and functions

Name

Concentration

Function

Characteristics

G

Pluronic F68

0.1 %

Shear protectant, anti foam

FoamAway

3%

Anti foam

Sterile, ready-to-use, pre-

diluted to 3%

Poloxamer 188 and

others

0.5-2 g/L

Shear protectant

A: compounds involved in cellular metabolism.

B: proteins.

C: growth factors.

D: metals, minerals.

E: antibiotics (antibiotics should, if used at all, be changed on a regular interval to avoid developing

antibiotic resistance).

F: others,

empty field: no data found.

G: shear protectants, some examples are given.

Data provided based on homepages of Thermo Fisher Scientific, Sigma-Aldrich, Gibco, Xell, and other

media suppliers [ 38, 39].

Upstream processing for viral vaccines

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