Salivary analysis of Secretory IgA (SIgA) is particularly useful for sport and exercise science, the analyte in saliva is "flow rate dependant", see below (7) .
Secretory Immunoglobulin A (SIgA) is a subclass of Immunoglobulin A (IgA), an antibody that plays a critical role in mucosal immunity.
SIgA is the main immunoglobulin found in mucous secretions from the tear glands, salivary glands, mammary glands, the respiratory system, the genito-urinary tract, and the gastrointestinal tract. (2)
SIgA is not synthesized by mucosal epithelial cells in these structures or derived from blood. Instead, it is produced by B-lymphocytes adjacent to the mucosal cells, then transported through the cell interiors, and released into the secretions from the cells. (3)
SIgA plays a key role in protecting vulnerable areas such as the oral cavity, lungs, and gut from invading pathogens. (2) Differences in SIgA levels in the saliva from different glands have been observed in humans, with the highest levels found in the minor saliva glands. (3,4) SIgA exhibits a diurnal rhythm, decreasing from the highest levels in the morning to the lowest in the evening. (5)
Levels of SIgA in saliva vary in response to physical and psychological stress through interactions with the autonomic nervous system. (6,7) SIgA levels in saliva are affected by flow rates, with concentrations normally decreasing as flow rates increase. Measurement of flow rates is advisable in order to express SIgA secretion as a function of time. (7)
Nutrition and Hydration Status is an important factor as demonstrated within this research from the Wildland Firefighter and their work on Immune Response
Firefighting Immune Response, SIgA
Important Publications
1. Judith E. Allgrovea*, Elisa Gomesa, John Hougha & Michael Gleesona (2008)
Effects of exercise intensity on salivary antimicrobial proteins and markers of stress in active men. Journal of Sports Sciences Volume 26, Issue 6, 2008
2. Holmgren, J., Czerkinsky, C. (2005). Mucosal immunity and vaccines. Nature Medicine, 11(4 Suppl), s45-53.
3. Brandtzaeg, P. (2007). Do salivary antibodies reliably reflect both mucosal and systemic immunity? Ann N Y Acad Sci, 1098, 288-311.
4. Crawford, J.M., Taubman, M.A., Smith D.J. (1975). Minor salivary glands as a major source of secretory immunoglobulin A in the human oral cavity. Science, 190(4220), 1206-9.
5. Li, T.-L., Gleeson, M. (2004). The effect of single and repeated bouts of prolonged cycling and circadian variation on saliva flow rate, immunoglobulin A and alpha-amylase responses. J Sports Sci, 22(11-12), 1015-1024.
6. Tsujita, S., Morimoto, K. (1999). Secretory IgA in saliva can be a useful stress marker. Env Health Prev Med, 4, 1-8.
7. Bishop, N.C., Gleeson, M. (2009). Acute and chronic effects of exercise on markers of mucosal immunity. Front Biosci, 1(14), 4444-56.
Link to Salimetrics SIgA Salivary Assay Kit and Assay Protocol
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