Fetal bovine serum
Encyclopedia
Fetal bovine serum or FBS (or fetal calf serum) is the portion of plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

 remaining after coagulation of blood, during which process the plasma protein fibrinogen
Fibrinogen
Fibrinogen is a soluble plasma glycoprotein, synthesised by the liver, that is converted by thrombin into fibrin during blood coagulation. This is achieved through processes in the coagulation cascade that activate the zymogen prothrombin to the serine protease thrombin, which is responsible for...

 is converted to fibrin
Fibrin
Fibrin is a fibrous, non-globular protein involved in the clotting of blood. It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site....

 and remains behind in the clot. Fetal bovine serum
Blood serum
In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...

 comes from the blood drawn from a bovine fetus
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...

 via a closed system of collection at the slaughterhouse
Slaughterhouse
A slaughterhouse or abattoir is a facility where animals are killed for consumption as food products.Approximately 45-50% of the animal can be turned into edible products...

 (aka abattoir). Fetal bovine serum is the most widely used serum-supplement for the in vitro cell culture of eukaryotic cells
Eukaryotic Cell
Eukaryotic Cell is an academic journal published by the American Society for Microbiology. The title is commonly abbreviated EC and the ISSN is 1535-9778 for the print version, and 1535-9786 for the electronic version....

. This is due to it having a very low level of antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

 and containing more growth factor
Growth factor
A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes....

s, allowing for versatility in many different cell culture applications.

The globular protein
Globular protein
Globular proteins, or spheroproteins are one of the two main protein classes, comprising "globe"-like proteins that are more or less soluble in aqueous solutions...

, bovine serum albumin
Bovine serum albumin
Bovine serum albumin is a serum albumin protein derived from cows. It is often used as a protein concentration standard....

(BSA), is a major component of fetal bovine serum. The rich variety of proteins in fetal bovine serum maintains cultured cells in a medium in which they can survive, grow, and divide.

Process

Fetal Bovine serum is a by-product of the meat industry. Fetal bovine serum, as with the vast majority of animal serum used in cell culture, is produced from blood collected at commercial slaughterhouses from cattle bred to supply meat destined for human consumption.

The first stage of the production process for fetal bovine serum is the harvesting of blood from the bovine fetus. The blood is collected aseptically into a sterile container or blood bag and then allowed to clot before centrifugation to remove the fibrin clot and the remaining blood cells from the clear yellow (straw) coloured serum. The serum is then stored frozen prior to further processing in order to make it suitable for cell culture.

The second stage of processing involves filtration, typically culminating in a sterile 0.1 micrometre membrane filter. When processed by a reputable commercial serum supplier the sterile fetal bovine serum is subject to stringent quality control testing and is supplied with a detailed Certificate of Analysis giving full test results and information concerning the origin of the material. Certificates of Analysis vary between commercial suppliers but usually include the following details; filtration statement, country of origin, cell growth performance testing, microbial sterility testing, screening for mycoplasma and virus, endotoxin, haemoglobin, IgG and total protein assays.

Ethical questions have been raised regarding the blood collection process with special emphasis on any potential discomfort caused to the fetus. Respected scientific investigation [1][2]has shown that the loss of blood circulation in the dam (mother animal) results in death within seconds of slaughter and that the fetus will be dead within a few minutes of the slaughter of the dam due to oxygen deprivation. In comparison, fetal bovine blood is collected from the bovine fetus only after the pregnant uterus has been removed from the slaughtered cow which, in a typical commercial slaughterhouse, means a delay of around 20 minutes from the time of slaughter. The time between maternal death and the start of fetal blood harvesting is relatively long and therefore means that there minimal possibility of brain activity in the fetus at the time of blood harvesting and hence minimal possibility of discomfort. Of course, it is important to balance the ethical concerns surrounding the welfare of the donor animal against the highly significant benefits that the use of fetal bovine serum brings to human and animal health.

Serum use

Fetal bovine serum is commercially available from many manufacturers, and because cells grown in vitro are highly sensitive, customers usually test specific batches to check for suitability for their specific cell type. When changing from batch to batch it is usual to adapt the cells to the new batch of material, for example, by mixing 50% of the old serum with 50% of the new serum and allowing the cells to acclimatise to the new material.

Serum is stored frozen to preserve the stability of components such as growth factors. When serum is thawed, some precipitation may be seen. This is a normal phenomenon and it does not compromise the quality of serum in any way. The precipitate may be removed by transferring the serum to sterile tubes and centrifuging for 5 minutes at 400 x g.

To limit the amount of precipitation, it is recommended that the serum is thawed in a refrigerator at 2-8˚C. The serum should be regularly mixed during this process. Repeated freeze/thaw cycles should be avoided and it is advisable to dispense the serum into single use aliquots before freezing.

Source history

Serum produced for use in the biotechnology industry and research sectors is highly regulated. The collection and movement of all animal derived products globally is strictly controlled. Veterinary control of animal derived products largely follows the regulations set by the EU (DG SANCO) and the US (USDA). The current regulation concerning the importation of animal by-products into the EU is covered by Regulation (EU) 1774/2002 and various derogations and amendments. This regulation will be replaced in March 2011 by Regulation (EU) 1069/2009 which was published on October 21, 2009.

FBS is a product collected worldwide with the main collections being centered in the United States, Australia, New Zealand, Canada, Central America, South America and Europe.

Global sales

Sales of FBS in 2008 were estimated to be 700,000 litres globally.

Major companies that collect and sell FBS globally are members of the ISIA, the International Serum Industry Association. Member companies are listed on the ISIA website. Full contact details are available through this portal and the ISIA will be able to answer any questions concerning the collection and use of this important resource.

The International Serum Industry Association, was incorporated June 2006. The ISIA promotes and assures quality and standards to a previously unstandardized industry. The ISIA Mission Statement: “The ISIA shall establish, promote and assure compliance with uncompromised standards of excellence and ethics in the business practices of the global animal serum and blood products supply industry. Our primary focus will be on safety and safe use of serum and animal derived products through proper origin traceability, truth in labeling and appropriate standardization and oversight.” www.serumindustry.org
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