Secretory Immunoglobulin A (SIgA) ELISA Kit

  • Created on the 23 February, 2017.


Secretory Immunoglobulin A (SIgA) is an antibody which has vital roles in mucosal immunity, it is also a subclass of immunoglobulin A (IgA). One of the main immunoglobulin in mucus secretions from the salivary glands, tear glands, mammary glands, gastrointestinal tract, genitourinary tract and the respiratory system. The intestinal cells can produce approx. 2-3g of SIgA every day, this tends to reach a peak during childhood and begins to decline after the age of sixty. Many people think of mucus being in the nose and sinuses, however, actually there is a greater amount present in the gut. The sticky lining of mucus is our primary line defence against any gastrointestinal pathogens such as bacteria, viruses, fungi, parasites and food proteins. The SIgA antibodies are able to prevent micro-organisms, carcinogens and food proteins from binding to the surface of absorptive cells. Essentially, they are able to attach themselves to invading pathogens, trap them in mucus and prevent them from going anyway. They effectively neutralise any damaging toxins given off and ensure that these are excreted from the body appropriately.

Secretory IgA is produced by B-lymphocytes that are located adjacent to the mucosal cells and then it is transported through the cell interiors until finally it is released as secretions from the cells. It is not synthesised by mucosal epithelial cells in these structures or even derived from blood. SIgA exhibits a diurnal rhythm, displaying highest levels in the morning which then decrease to the lowest in the evening.

There is a difference in the levels that are present in saliva depending on the secreting glands, with the highest levels found in minor saliva glands. The concentrations of secretory IgA in saliva vary in response to psychological and physical stress through a complex interaction with the autonomic nervous system. The levels of SIgA in saliva can also be affected by the flow rates, where usually the concentrations tend to decrease as flow rates increases. Therefore, it is recommended to measure the flow rate in order to accurately express SIgA secretion as a function of time.


Secretory IgA ELISA kit is an accurate in vitro quantitative method for detecting secretory immunoglobulin A (SIgA) in human saliva, serum, urine and milk samples. This assay has a minimum sensitivity detection limit of 1.0 µg/ml.


The minimum sensitivity detection limit of secretory immunoglobulin A (SIgA) using this human secretory IgA ELISA kit was approximately 1.0 µg/ml. The dynamic assay range for this kit is 2.0 – 400.0 µg/ml.


  1. An update on minor salivary gland secretions. Eur J Oral Sci. (2010) 118 (5): 435-42. Review. Eliasson L. and Carlén A.
  2. SIgA binding to mucosal surfaces is mediated by mucin-mucin interactions. PLoS One. (2015) 10 (3): e0119677. Gibbins H.L., et al.
  3. A simple and rapid competitive enzyme-linked immunosorbent assay (cELISA) for high-throughput measurement of secretory immunoglobulin A (sIgA) in saliva. Talanta. (2010) 82 (1): 432-6. Wang D., et al.
  4. Tear Fluid SIgA as a Noninvasive Biomarker of Mucosal Immunity and Common Cold Risk. Med Sci Sports Exerc. (2016) 48 (3): 569-77. Hanstock H.G., et al.
  5. Secretory A immunoglobulin, total proteins and salivary flow in Recurrent Aphthous Ulceration. Braz J Otorhinolaryngol. (2007) 73 (3): 323-8. Martinez Kde O., et al.


  • Full Name: Secretory Immunoglobulin A (SIgA) ELISA Kit
  • Reactivity: Human
  • Sample Type: Saliva, Serum, Urine, Milk
  • Sensitivity: 1.0 µg/ml



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Lecturer / University College London (UCL)

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Lead Scientists / AstraZeneca

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Purchasing / University of Oxford