Immunoglobulin A (IgA) is a critical antibody isotype central to mucosal immunity and systemic immune regulation. Structurally, IgA exists in two primary forms: monomeric IgA in serum (predominantly IgA1) and dimeric or polymeric secretory IgA (sIgA) at mucosal surfaces. Each IgA molecule comprises two α-heavy chains and two light chains (κ or λ), forming a flexible Y-shaped structure stabilized by disulfide bonds. The α-heavy chain contains three constant domains (Cα1–Cα3), with the Fc region (Cα2–Cα3) facilitating interactions with Fcα receptors (FcαRI) and the polymeric immunoglobulin receptor (pIgR). Secretory IgA incorporates a J-chain and a secretory component, which enhance its stability in protease-rich mucosal environments. Extensive glycosylation of IgA further modulates its solubility, receptor binding, and resistance to microbial degradation. IgA is the predominant antibody at mucosal surfaces (e.g., respiratory, gastrointestinal, and urogenital tracts), where it neutralizes pathogens, prevents microbial adherence, and regulates commensal microbiota. Secretory IgA mediates immune exclusion by trapping pathogens in mucus for mechanical clearance, while serum IgA contributes to systemic immune regulation by dampening inflammatory responses via FcαRI signaling. Additionally, IgA engages in eosinophil-mediated antiparasitic defense and modulates allergic reactions through interactions with immune cells. Human IgA shares conserved structural motifs with IgA from primates and rodents, particularly in the α-chain constant domains. However, species-specific variations in glycosylation patterns, J-chain association, and secretory component binding necessitate species-specific detection assays. For instance, human IgA1’s unique hinge region, rich in proline and O-glycosylation sites, distinguishes it from murine IgA, which lacks this feature. Applications of the Human IgA ELISA Kit: This OneStep Human IgA ELISA kit enables rapid, accurate quantification of IgA in serum, plasma, or cell culture supernatants. Advantages of this OneStep ELISA Kit Design: Simplified Workflow: Combines sample incubation and detection in a single step, eliminating intermediate washing and reducing hands-on time. High Efficiency: Achieves results within 1 hours, ideal for high-throughput studies or urgent diagnostics. Enhanced Precision: Minimizes procedural variability and cross-contamination risks through optimized reagent formulation. Broad Compatibility: Validated for diverse biological matrices, ensuring flexibility in experimental design. This kit’s streamlined protocol and robust performance make it an indispensable tool for researchers and clinicians seeking reliable IgA quantification in time-sensitive or resource-limited settings.
Standard curve
Example of Human IgA standard curve in Assay Diluent #1.
Linearity
The concentrations of Human IgA were measured and interpolated from the target standard curves and corrected for sample dilution.
#1 sample is undiluted samples are as follows: Human Serum was 1.6×10^5fold dilution. The interpolated dilution factor corrected values are plotted. The mean target concentration was determined to be 2.39 mg/mL in Human Serum.
#2 sample is undiluted samples are as follows: Human Plasma was 1.6×10^5fold dilution. The interpolated dilution factor corrected values are plotted. The mean target concentration was determined to be 1.62 mg/mL in Human Plasma.
To assess the linearity of the assay, in cell culture media with high concentrations of Rat IgA in various matrices and diluted with the appropriate Calibrator Diluent to produce samples with values within the dynamic range of the assay.
To assess the linearity of the assay, in serum and plasma with high concentrations of Rat IgA in various matrices and diluted with the appropriate Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Specificity
Test the different specificity of IgA standards and serum: sample #1 is Mouse IgA (100 ng/mL); sample #2 is Rat IgA (100 ng/mL); sample #3 is Human IgA (100 ng/mL). sample #4 is Mouse serum; sample #5 is Rat serum; sample #6 is Human serum; sample #7 is blank.
Protocol Diagram