Description

The Calbiotech Secretory IgA (sIgA) ELISA Kit is intended for the quantitative measurement of sIgA in human stool or saliva

Clinical Significance

Secretory IgA (SIgA) serves as the first line of defense in protecting the intestinal epithelium from enteric toxins and pathogenic microorganisms. Through a process known as immune exclusion, SIgA promotes the clearance of antigens and pathogenic microorganisms from the intestinal lumen by blocking their access to epithelial receptors, entrapping them in mucus, and facilitating their removal by peristaltic and mucociliary activities. In addition, SIgA functions in mucosal immunity and intestinal homeostasis through mechanisms that have only recently been revealed. In just the past several years, SIgA has been identified as having the capacity to directly quench bacterial virulence factors, influence composition of the intestinal microbiota by Fab-dependent and Fab-independent mechanisms, promote retro-transport of antigens across the intestinal epithelium to dendritic cell subsets in gut-associated lymphoid tissue, and, finally, to downregulate proinflammatory responses normally associated with the uptake of highly pathogenic bacteria and potentially allergenic antigens.1

Principle of the Test

The Calbiotech Secretory IgA (sIgA) kit is a solid phase direct ELISA sandwich method. The standards, samples and controls are added into designated wells, coated with anti-sIgA monoclonal antibody, along with the incubation buffer. After a simple washing step, an anti-SIgA enzyme conjugate reagent is added into each well. After the excess enzyme conjugate is washed out, a chromogenic substrate (TMB) is added into each well. Upon the addition of the substrate, the intensity of color developed is directly proportional to the concentration of sIgA in the samples. A standard curve is generated relating color intensity to the concentration of sIgA.

1. N.J. Mantis, et.al. (June 2011). “Secretory IgA’s complex roles in immunity and mucosal homeostasis in the gut.” Mucosal Immunology (2011) 4, 603–611; doi:10.1038/mi.2011.41;