α₂-Macroglobulin: Fast and sensitive analysis with monoclonal antibodies

Abstract

Monoclonal antibodies specific for human α₂-macroglobulin (α₂-M) have been produced. The antibodies were used in conjunction with commercially available rabbit antibody to α₂-M in a sandwich enzyme immunoassay. With incubation times of only 2 h with sample and 30 min with enzyme substrate, the useful range was 10–200 μg α₂-M per litre; longer incubation time increased the sensitivity. The intra-assay coefficient of variation (CV) was 5%; the inter-assay CV was 7%. The assay does not discriminate between native, methylamine-inactivated, and trypsin-treated α₂-M. The monoclonal antibodies are also useful for immunocytochemistry and for immunoprecipitation of α₂-M.

Key words:

• ELISA
• enzyme-linked immunosorbent assay
• immunocytochemistry
• immunoimmobilization
• plasma proteins