PRODUCTION OF CONFORMATION-SPECIFIC MONOCLONAL-ANTIBODIES AGAINST ALPHA(2) MACROGLOBULIN AND THEIR USE FOR QUANTITATION OF TOTAL AND TRANSFORMED ALPHA(2) MACROGLOBULIN IN HUMAN BLOOD

Monoclonal antibodies against the human proteinase inhibitor, alpha2 macroglobulin, have been produced by immunizing BALB/c mice with alpha2 macroglobulin reacted with methylamine. Two antibodies have been characterized in detail with respect to their binding to native a2 macroglobulin and to different derivatives of the inhibitor. The antibody alpha-1 was found to recognize only those forms of the inhibitor which were transformed by reaction with different proteinases or with methylamine. Binding of alpha-1 was mapped to a specific epitope localized within a distance of 138 amino acid residues from the C terminal end of alpha2 macroglobulin. The C terminal end is assumed to be exposed during the transformation of the inhibitor and harbours the receptor recognition site. The monoclonal antibody alpha-11 was found to bind to all forms of the inhibitor indicating that its epitope is located in a region not involved in major conformational changes of the inhibitor. On the basis of the different reactivity patterns of alpha-1 and alpha-11 two enzyme-linked immunosorption assays were established for quantitation of total and transformed alpha2 macroglobulin in human blood. The concentration of the two forms have been determined in a population of 114 healthy individuals giving values of 254 +/- 6.6 mg/dl (mean +/- SEM) of total alpha2 macroglobulin and 1.07 +/- 0.05 mg/dl (means +/- SEM) of the transformed inhibitor.