AMA-M2

AMA-M2 ELISA is an test system for the quantitative measurement of IgG class autoantibodies against mitochondrial M2 subtype antigen in human serum or plasma.This product is intended for professional in vitro diagnostic use only.Highly purified mitochondrial M2 subtype antigen is bound to microwells. Antibodies against the coated antigen, if present in diluted patient sample, bind to the respective antigen. Washing of the microwells removes unbound unspecific serum and plasma components. Horseradish peroxidase (HRP) conjugated anti-human antibodies immunologically detect the bound patient antibodies forming a conjugate/antibody/antigen complex. Washing of the microwells removes unbound conjugate. An enzyme substrate in the presence of bound conjugate hydrolyzes to form a blue colour. The addition of an acid stops the reaction forming a yellow end-product. The intensity of this yellow colour is measured photometrically at 450 nm. The amount of colour is directly proportional to the concentration of antibodies present in the original sample. Anti-mitochondrial antibodies (AMA) are a heterogeneous group of autoantibodies directed against various proteins that are located in the outer and inner membrane of itochondria. Specific anti-mitochondrial antibodies have been described for the primary biliary cirrhosis (PBC) as subtypes M2, M4, M8 and M9. Other AMA subtypes are relatedto other diseases, like collagenosis (AMA-M5) and drug induced LE and Hepatitis (AMA-M3 and AMA-M6). The heterogeneously reacting specific anti-mitochondrial antibodies of the M2 subtype are directed against three related proteins of the alpha-keto acid dehydrogenase complex which is located at the inside of the mitochondrial membrane. The recognized major epitope is located on the E2 subunit and the protein X of the pyruvate dehydrogenase complex (PDC). Additionally AMA-M2 autoantibodies recognise the (E1a und E1b) subunits of the same complex and the E2 subunit of several other multi enzyme complexes, such as the 2-oxo-glutarate dehydrogenase complex (OGDC) and the branched chain 2-oxo acid dehydrogenase complex (BCOADC). Using HEp2 Cell monolayers for indirect immune fluorescence AMA-M2 autoantibodies are characterised as a finespeckledcytoplasmic, perinuclear condensed fluorescence pattern. For differential diagnosis of the primary biliary cirrhosis (PBC) determination of AMA-M2 by ELISA is recommended because of its high sensitivity and specificity. In patients with other autoimmune diseases determination of AMA antibodies allows an early screening for the occurrence of subtype M2 and M9 antibodies which may be related with the development and / or association of PBC. Profiling the AMA subtypes allows an immunological and prognostic classification of the primary biliary cirrhosis. Beginning cases of symptomatic PBC often exhibit only AMA-M2 subtype antibodies (sometimes in combination with AMA-M9), whereas progressive cases and mixed syndromes with chronic acute hepatitis (CAH) are related with the occurrence of AMA-M2, -M4 and -M8 antibody subtypes.