Secretion assay is a process used in cell biology to identify cells that are secreting a particular

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

(usually a

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

). It was first developed by ''Manz et al.'' in 1995. Usually, a cell that is secreting the protein of interest is isolated using an antibody-antibody complex that coats the cell and is able to "catch" the secreted molecules. The cell is then detected by another

fluorochrome A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with sev ...

-labelled

antibody An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

, and is subsequently extracted using a process called

fluorescent-activated cell sorting Flow cytometry (FC) is a technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the fl ...

(FACS). The FACS method is broadly similar to the ''enzyme-linked immunosorbent assay'' (

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presen ...

) antibody format, except that the encapsulated cells remain intact. This is advantageous as the cells are still living after the extraction has taken place. Further advances now mean that it is possible to extract the secreting cells using a magnetic-based separation system or using a

flow cytometer Flow cytometry (FC) is a technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the fl ...

. A number of commercial applications exist for secretion assay. One such example is the Gel Microdrop (GMD) technology, developed by

One Cell Systems 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1 ...

. One Cell asserts that GMD typically recovers a higher number of viable secreting cells than other methods, whilst ignoring any cells which are not secreting the desired protein.

References

External links

One Cell Systems
- Gel Microdrop (GMD) Secretion Assay technology. Cytokines Protein methods {{Cell-biology-stub

References

Further reading

External links