Culture media for propagation of mammalian cells, viruses, and other biologicals.

In this brief review, we have illustrated the historical development of the growth media commonly employed for the propagation of cultured mammalian cells. While substantial progress has been achieved, the field may best be described as conservative and pragmatic. To date, the function of many components of the growth medium essential for cellular proliferation and biological production has not been precisely defined at the molecular level. Thus, for most large-scale biological production requirements, as well as for routine cell culture and bench-scale pilot development, the traditional enriched culture medium supplemented with fetal bovine serum represents the most convenient culture system. Many cell types may be more economically grown without reduction in biological yield by substituting alternative mammalian sera. Where reduction of total protein or greater definition of growth medium components outweighs the use of more universally applicable culture media, substitution of serum-free, customized formulations of highly enriched growth medium plus defined growth factors may be of significant utility. Optimization of mammalian cell culture media for large-scale biological production should include the following: An initial time investment to optimize the cell culture medium by enriching intermediary metabolite composition (rather than expecting serum or additional growth factors to perform nutritional functions) may result in higher productivity and reduced cost. When screening potential growth media for biological production applications, proliferative rate should not be the sole criterion for performance. Although rapid, logarithmic growth is advantageous to establish large-scale cultures, the maximal cell density and duration of the viable, productive period must also be weighed. Many cell types generate the highest titers of biological product either at stationary phase or under mildly stressful ("controlled death") conditions suboptimal for cellular replication. Thus, the ultimate determinant of growth medium efficacy is neither the degree of definition of medium composition nor the cellular proliferative rate, but the ability to support synthesis of substantial titers of the desired product at reasonably high purity.