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 m acroglobulin, have been produced by immunizing BALB/c mice with alpha2 macroglobulin reacted with methylamine. Two antibodies have been char acterized in detail with respect to their binding to native a2 macrogl obulin and to different derivatives of the inhibitor. The antibody alp ha-1 was found to recognize only those forms of the inhibitor which we re transformed by reaction with different proteinases or with methylam ine. Binding of alpha-1 was mapped to a specific epitope localized wit hin a distance of 138 amino acid residues from the C terminal end of a lpha2 macroglobulin. The C terminal end is assumed to be exposed durin g the transformation of the inhibitor and harbours the receptor recogn ition site. The monoclonal antibody alpha-11 was found to bind to all forms of the inhibitor indicating that its epitope is located in a reg ion 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 quantita tion of total and transformed alpha2 macroglobulin in human blood. The concentration of the two forms have been determined in a population o f 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.