Tissue Transglutaminase Ab IgG ELISA Kit (tTG)

Full Name: Tissue Transglutaminase Ab IgG ELISA Kit (tTG)
Reactivity: Human
Sample Type: Plasma, Serum
Sensitivity: 1.0 U/ml

BACKGROUND

Structurally, tissue transglutaminase (tTG) consists of four domains: an N-terminal β-sandwich domain that anchors the enzyme to fibronectin in the extracellular matrix, a catalytic core domain that houses the active site, and two C-terminal β-barrel domains that regulate access to the active site. The active site contains an essential cysteine residue required for the transamidation reaction. Binding of calcium ions induces conformational changes in tTG that increase accessibility of the active site and activate its crosslinking function.

In the intestine, tTG deamidates gluten peptides by converting glutamine residues to glutamate. This increases the binding affinity of gluten peptides for HLA-DQ2/8 molecules displayed on antigen presenting cells. Presentation of deamidated gluten peptides triggers activation of inflammatory CD4+ T cells specific for gluten, leading to the intestinal damage and clinical manifestations of celiac disease. tTG autoantibodies are produced in celiac disease and used clinically to aid diagnosis.

Beyond celiac disease, aberrant expression and activity of tTG have been implicated in numerous other disease processes such as fibrosis, cancer, neurodegeneration, thrombosis, and autoimmunity. For example, excessive crosslinking activity of tTG can contribute to extracellular matrix accumulation in fibrotic disorders.

INTENDED USE

Human tissue transglutaminase Ab IgG ELISA kit can be used for determining in-vitro quantitative levels of IgG class auto-antibodies to tissue transglutaminase (anti-tissue transglutaminase, tissue transglutaminase antibody IgG, TG2-IgG, tTG) in human serum or plasma. This assay has a minimum analytical sensitivity limit of 1.0 U/ml.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• Divisible Microplate: Consisting of 12 modules of 8 wells, recombinant tTG antibodies bound to microwells.
• Calibrators (A-F): Concentration 0-200 U/ml, made up from tissue transglutaminase antibody.
• Controls Positive and Control Negative: Containing human tissue transglutaminase antibody.
• Sample Buffer (5x).
• Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
• TMB Substrate.
• Stop Solution: Contains acid.
• Wash Buffer (50x Concentrated).
• Instruction Manual.
• Certificate of Analysis.

SENSITIVITY

The minimum detection sensitivity level of human tissue transglutaminase Ab IgG (tTG, TG2-IgG, anti-tissue transglutaminase IgG) using current tissue transglutaminase IgG ELISA kit was 1.0 U/ml. The dynamic range for this assay is 5.0 – 200.0 U/ml.

ASSAY CHARACTERISTICS

– Limit Of Detection (LOD): 1 U/ml.
– Measuring Range: 0 – 200 U/ml
– Results Interpretation: Negative <10 U/ml, Positive ≥ 10 U/ml.
– Expected Values: Cut-off 10 U/ml.
– Interference: None.
– Intra Assay: 6.1 – 6.7%
– Inter Assay: 8.8 – 10.9%
– Linearity: 93 – 108%
– Clinical Diagnosis: Sensitivity (72.1%), Specificity (100.0%), Overall agreement (91.0%).

REFERENCES

1. Role of human-tissue transglutaminase IgG and anti-gliadin IgG antibodies in the diagnosis of coeliac disease in patients with selective immunoglobulin A deficiency. Dig Liver Dis. (2004) 36 (11): 730-4. Lenhardt A., et al.
2. IgG anti-tTG responses in different autoimmune conditions differ in their epitope targets and subclass usage. Mol Immunol. (2015) 67 (2 Pt B): 369-76. Comerford R., et al.
3. A rare case of Addison’s disease, hepatitis, thyreoiditis, positive IgG anti-tissue transglutaminase antibodies and partial IgA deficiency. Cent Eur J Immunol. (2016) 41 (2): 217-20. Baleva M.P., et al.

OTHER RELATED ELISA KITS

• tTG IgA ELISA Kit
• Gliadin IgG ELISA Kit
• tTG Screen ELISA Kit