Monoclonal antibodies to enzymes

ELISA using monoclonal antibody to human serum arylesterase

ELISA for determining arylesterase content in human serum has been developed by the one-step sandwich method using 2 monoclonal antibodies. While the content of arylesterase in healthy adults was 81 +/- 25 mg/l, a decrease was observed in patients with liver cirrhosis, where the mean +/- SD was 37 +/- 7 mg/l. ELISA of human serum arylesterase correlated with the activity determined by a specific substrate assay we devised recently.

Incidence and properties of aspartate aminotransferase-immunoglobulin complexes in patients with a high serum aspartate to alanine aminotransferase ratio

Sera of 260 patients with high serum aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1; AST)/alanine aminotransferase (L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2; ALT) ratio (greater than 2.0) and high serum AST (greater than 45 IU/1) were selected and tested for the presence of immunoglobulin complexed-AST, by using immunoprecipitation reaction and counterimmunoelectrophoresis. The macromolecular AST was confirmed by size-exclusion high-performance liquid chromatography (HPLC). 34 patients out of 260 were found to have AST-immunoglobulin complexes (13.1%). The classes of AST-linked immunoglobulins were identified to be alpha in 28 cases (82.4%, P less than 0.01), mixed type of alpha and gamma in 5 cases (14.7%) gamma in one case (2.9%). Positive frequency was the highest in liver malignancies, either primary (9/26, 34.6%) or metastatic (7/17, 42.2%), followed by other malignancies (6/55, 10.9%) and chronic liver diseases (4/22, 18.2%). Thus, it can be strongly suggested that the immunoglobulin A complexed-AST is frequently found in association with liver malignancies.

Monoclonal antibodies to barley alpha-amylase I: production, characterization, and application to a specific immunoassay

Monoclonal antibodies (MAbs) to barley alpha-amylase I have been produced, purified and characterized. Six are specific for the alpha-amylase I isoform, while one also reacts with alpha-amylase II. All but one recognize the antigen in solution. Topology of the MAbs was investigated by additivity in ELISA, which led us to subdivide them into four groups. An immunoassay was developed using one of these MAbs, to measure alpha-amylase I activity in an extract containing both isoforms.