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Secretory IgA (sIgA) ELISA for Human Stool, Saliva (ImmuChrom)

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The ImmuChrom Secretory IgA ELISA Kit is intended for the quantitative determination of sIgA in stool and saliva. This immunoassay allows an easy, rapid and precise quantification of secretory IgA. The kit includes all reagents ready to use for preparation of the samples.

Secretory IgA is comprised of two immunglobulin A molecules, which are joined by a J-protein and a secretory component. The secretory component is synthesized by epithelial cells of the mucous membrane of gastrointestinal, respiratory and urogenitaltract. It is also produced by the saliva, tear and mammary glands. The plasma cells in the subendothelial area of mucous membranes are releasing a complex of two IgA-molecules, which are joined over the J-protein. This complex is binding to a secretory component, located at the surface of the epithelia cell. After binding, the sIgA is transported across the cell and excreted by exocytosis. The determination of secretory IgA (sIgA) allows a first overview of the functionality of the gastrointestinal associated immune system (GALT). With this the secretory power and the degree of stimulation of the plasma cells of the intestinal submucosa is determined.


Sandwich ELISA, HRP-labelled antibody

Other names

secretory IgA, sIgA, secretory immunoglobulin A antibody

Principle of Method

The sIgA-ELISA test determines human secretory IgA according to the “sandwich”-principle. sIgA in samples, standard and controls binds to antibodies, which are coated on the microtiterplate. After the washing step, a peroxidase labeled detection antibody is added. A second washing step is followed by the addition of the substrate which is converted to a colored product by the peroxidase. The reaction is terminated by the addition of an acidic stop solution. The optical densities are read at 450 nm (against the reference wavelength 620 nm) in a microtiterplate reader. The sIgA concentration can be calculated from the standard curve.

Sample Types

Stool, Saliva

Sample Volume

  • Stool: 100 mg (collected sample) in glass/plastic vials or ~20mg in stick vials
  • Saliva: 10 µl of centrifuged sample.

Standard Curve

Example standard curve of Immuchrom sIgA ELISA

Calibration Range:  22.2 ng/ml - 600 ng/ml

Limit of Detection

3.1 ng/ml

Intra-assay (Within-Run) C.V.

5.4 %

Inter-assay (Run-to-Run) C.V.

6 %

Intended Use

This assay is intended for research use only and is not for use in diagnostic procedures.


Product References

  • Jendraszak, Magdalena et al. “Impact of Biometric Patient Data, Probiotic Supplementation, and Selected Gut Microorganisms on Calprotectin, Zonulin, and sIgA Concentrations in the Stool of Adults Aged 18-74 Years.” Biomolecules vol. 12,12 1781. 29 Nov. 2022, doi:10.3390/biom12121781
  • Eor, Ju Young et al. “Effect of Probiotic-Fortified Infant Formula on Infant Gut Health and Microbiota Modulation.” Food science of animal resources vol. 43,4 (2023): 659-673. doi:10.5851/kosfa.2023.e26
  • Karolkiewicz, Joanna et al. “No effects of a 4-week post-exercise sauna bathing on targeted gut microbiota and intestinal barrier function, and hsCRP in healthy men: a pilot randomized controlled trial.” BMC sports science, medicine & rehabilitation vol. 14,1 107. 16 Jun. 2022, doi:10.1186/s13102-022-00497-z
  • Velikova, Tsvetelina et al. “Lactobacilli Supplemented with Larch Arabinogalactan and Colostrum Stimulates an Immune Response towards Peripheral NK Activation and Gut Tolerance.” Nutrients vol. 12,6 1706. 7 Jun. 2020, doi:10.3390/nu12061706
  • Ustinova, Monta et al. “Metformin strongly affects transcriptome of peripheral blood cells in healthy individuals.” PloS one vol. 14,11 e0224835. 8 Nov. 2019, doi:10.1371/journal.pone.0224835
  • Edman, Maria C et al. “Increased Cathepsin S activity associated with decreased protease inhibitory capacity contributes to altered tear proteins in Sjögren's Syndrome patients.” Scientific reports vol. 8,1 11044. 23 Jul. 2018, doi:10.1038/s41598-018-29411-9

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