Best practices for the use and evaluation of animal serum as a component of cell culture medium

Abstract

Animal serum is a common additive for cell culture medium and is often required at 5 to 10% (v/v) for the attachment and growth of primary and continuous anchorage-dependent (monolayer) cultures. The use of animal serum in cell culture medium confers several advantages and also some risks. This article discusses the use of animal serum as a component of cell culture medium. The best practices associated with the sourcing, storage, thawing, testing, and mitigation of risk associated with the use of animal sera are among the topics described in this article.

Glossary

Adventitious agents

Infectious agents which can contaminate cell cultures, such as viruses and bacteria.

Anchorage-dependent cells or cultures

Cells, or cultures derived from them, which will grow, survive, or maintain function only when attached to a surface such as glass or plastic. The use of this term does not imply that the cells are normal or that they are or are not neoplastically transformed.

Aneuploid

The situation which exists when the nucleus of a cell does not contain an exact multiple of the haploid number of chromosomes; one or more chromosomes being present in greater or lesser number than the rest. The chromosomes may or may not show rearrangements.

Cell line

A cell line arises from a primary culture at the time of the first successful subculture. The term “cell line” implies that cultures from it consist of lineages of cells originally present in the primary culture. The terms “finite” or “continuous” are used as prefixes if the status of the culture is known. If not, the term line will suffice. The term “continuous line” replaces the term “established line.” In any published description of a culture, one must make every attempt to publish the characterization or history of the culture. If such has already been published, a reference to the original publication must be made. In obtaining a culture from another laboratory, the proper designation of the culture, as originally named and described, must be maintained and any deviations in cultivation from the original must be reported in any publication.

Chemically defined medium

A nutritive solution for culturing cells in which each component is of known chemical structure.

CHO

Chinese hamster ovary

Continuous cell culture

A culture which is apparently capable of an unlimited number of population doublings, often referred to as an immortal cell culture. Such cells may or may not express the characteristics of in vitro neoplastic or malignant transformation.

Dialysis/charcoal stripping

A treatment of serum intended to remove certain low molecular weight protein complexes, polar and non-polar chemicals, hormones, cytokines, glucose, amino acids, antibiotics, and other exogenous molecules (dialysis), or to remove non-polar constituents of serum such as hormones, growth factors, cytokines, and lipid-enveloped viruses (charcoal stripping).

Diploid

The situation where the nucleus of the cell contains the normal (i.e., two times the haploid) number of chromosomes.

EBE

Equine (horse) bronchial fibroblast

EMA

European Medicines Agency

FBS

Fetal bovine serum

GMP

Good manufacturing practices

Heat inactivation

The process of raising the temperature of serum to 56°C for a short period of time (typically 30 min) to inactivate complement.

IgG

Immunoglobulin G

IgG stripping

A treatment of serum intended to remove undesired antibodies from the serum.

NS0

Mouse (murine) myeloma cell line

Passage

The transfer or transplantation of cells, with or without dilution, from one culture vessel to another. It is understood that any time cells are transferred from one vessel to another, a certain portion of the cells may be lost and, therefore, dilution of cells, whether deliberate or not, may occur. This term is synonymous with the term “subculture.”

Passage number

The number of times the cells m the culture have been subcultured or passaged. In descriptions of this process, the ratio or dilution of the cells should be stated so that the relative cultural age can be ascertained.

Plating efficiency

This is a term which originally encompassed the terms, “Attachment (“Seeding”) efficiency”, “Cloning efficiency,” and “Colony forming efficiency” and which is now better described by using one or more of them in its place as the term “plating” is not sufficiently descriptive of what is taking place.

Population doubling time

The interval, calculated during the logarithmic phase of growth in which, for example, 1.0 × 106 cells increase to 2.0 × 106 cells. This term is not synonymous with “cell generation time.”

Primary culture

Primary cultureA culture started from cells, tissues, or organs taken directly from organisms. A primary culture may be regarded as such until it is successfully subcultured for the first time. It then becomes a “cell line.”

Sp2/0

Mouse (murine) myeloma cell line, multi-drug resistant.