Serum (blood)

Clinical and laboratory uses

The serum of convalescent patients successfully recovering (or already recovered) from an infectious disease can be used as a biopharmaceutical in the treatment of other people with that disease, because the antibodies generated by the successful recovery are potent fighters of the pathogen. Such convalescent serum (antiserum) is a form of immunotherapy.

Serum is also used in protein electrophoresis, due to the lack of fibrinogen which can cause false results.

Fetal bovine serum (FBS) is rich in growth factors and is frequently added to growth media used for eukaryotic cell culture. A combination of FBS and the cytokine leukemia inhibitory factor was originally used to maintain embryonic stem cells, but concerns about batch-to-batch variations in FBS have led to the development of serum substitutes.

Vertebrate sera (such as FBS) or invertebrate hemolymph were also used for the growth of insect cell lines as a source of nutrients and growth factors. Cost and other factors lead to the development of replacement media and cell lines that grow well in these media.

Purification strategies

Blood serum and plasma are some of the largest sources of biomarkers, whether for diagnostics or therapeutics. Its vast dynamic range, further complicated by the presence of lipids, salts, and post-translational modifications, as well as multiple mechanisms of degradation, presents challenges in analytical reproducibility, sensitivity, resolution, and potential efficacy. For analysis of biomarkers in blood serum samples, it is possible to do a pre-separation by free-flow electrophoresis that usually consists of a depletion of serum albumin protein. This method enables greater penetration of the proteome via separation of a wide variety of charged or chargeable analytes, ranging from small molecules to cells.

Usage note

Like many other mass nouns, the word serum can be pluralized when used in certain senses. To speak of multiple serum specimens from multiple people (each with a unique population of antibodies), physicians sometimes speak of sera (the Latin plural, as opposed to serums). Etymologically serum is derived from the Proto-Indo-European *ser- ("to flow, run").

References

References

1. "serum". The Free Dictionary.
2. Kaplan, Larry. (2005-10-06). "Serum Toxicology". Columbia University.
3. (August 1992). "Measuring cytokine levels in blood. Importance of anticoagulants, processing, and storage conditions". Journal of Immunological Methods.
4. (6 November 1998). "Embryonic Stem Cell Lines Derived from Human Blastocysts". Science.
5. (June 2011). "Human embryonic stem cells: derivation, maintenance and cryopreservation". International Journal of Stem Cells.
6. (2007). "Baculovirus and Insect Cell Expression Protocols".
7. (August 2008). "Analysis of human plasma proteins: a focus on sample collection and separation using free-flow electrophoresis". Expert Review of Proteomics.