Medizym® Anti-IA2 is an enzyme immunoassay (ELISA) for the quantitative determination of autoantibodies to Islet Cell Antigen IA2 (IA2 Abs), also called ICA512 in human serum. IA2 shares domain homology with protein phosphotyrosine phosphatase, but does not have any such activity. IA2 localizes to the dense granules in pancreatic beta cells and has been postulated to play a role in regulating insulin secretory granule content. The appearance of IA2 autoantibodies seems to be correlated with the rapid progression to overt type 1 diabetes.
Microtiter plate
A MP 1 piece 12 breakable microtiter strips (ready-to-use), 8 wells per strip, each well coated with recombinant human IA2
Calibrator
0 – 4 CAL
5 x 1.0 mL Colored dilutions of human serum (ready-to-use; contains ProClin 950). The antibody activities are indicated on the quality control certificate.
Positive control
CII CONTROL | + 1 x 1.0 mL Colored dilution of human serum (ready-to-use; contains ProClin 950). The antibody activity is indicated on the quality control certificate.
IA2-Biotin
H START 1 x 0.2 mL Concentrated start reagent biotinylated IA2 (contains sodium azide)
Diluent for IA2-Biotin
J BUF H 1 x 20 mL Colored solution (ready-to-use; contains sodium azide and ProClin 950)
Streptavidin-peroxidase
(SA-POD) D CONJ 1 x 0.2 mL Concentrated streptavidin conjugated to horseradish peroxidase (100x)
Diluent for SA-POD
G BUF D 1 x 20 mL Solution (ready-to-use; contains ProClin 950)
Wash buffer
B WASHB 1 x 100 mL Concentrated solution (10x; contains ProClin 950)
Substrate
E SUB 1 x 15 mL 3,3´,5,5´-Tetramethylbenzidine (ready-to-use)
Stop solution
F STOP 1 x 15 mL 0.25 M Sulfuric acid(ready-to-use)
Type 1 diabetes, also known as insulin-dependent diabetes mellitus (IDDM), results from a chronic autoimmune destruction of the insulin-secreting pancreatic beta cells, probably initiated by exposure of genetically susceptible host to an environmental agent. Autoimmune destruction of beta cells is thought to be completely asymptomatic until 80 -90 % of the cells are lost. This process may take years to complete andmay occur at any time.
During the preclinical phase, this autoimmune process is marked by circulating autoantibodies to beta cell antigens. These autoantibodies are present years before the onset of type 1 diabetes and prior to clinical symptoms. Early studies utilized the immunofluorescence test for islet-cell antibodies (ICA), which has been difficult to standardize and is now replaced by a combination of several radioimmunoassays for antibodies against specific beta cell antigens, such is insulin (IAA), glutamic acid decarboxylase (GAD) and tyrosine phosphatase ICA 512 (IA2).
IA2, a member of the protein tyrosine phosphatases family is localized in the dense granules of pancreatic beta cells and the second defined recombinant islet cell antigen. IA2 shares sequence identity with the islet cell antigen 512. The higher frequency of antibodies to IA2 is explained by the presence of autoantibodies directed to the COOH terminus of IA2 which is lacking in the ICA512 molecule.
IA2 autoantibodies are present in the majority of individuals with new-onset type 1 diabetes and in individuals in the pre-diabetic phase of the disease. The appearance of autoantibodies to IA2 seems to be correlated with the rapid progression to overt type 1 diabetes.
The combination of tests for GAD65 and IA2 autoantibodies is highly relevant for risk assessment of type 1 diabetes in children and adolescence. The screening for GAD65 and IA2 autoantibodies detect more than 90 % of subjects at risk for type 1 diabetes and may, therefore, possess the potential to replace ICA technique.
