DIFFERENTIATION OF HUMAN PHOSPHOLIPASE-A(2) ISOENZYMES IN SERUM AND OTHER BODY-FLUIDS WITH USE OF MONOCLONAL-ANTIBODIES

Elevated phospholipase A2 activities in serum were measured in patient s suffering from acute pancreatitis or various inflammatory diseases. The photometric phospholipase A assay of Hoffmann & Neumann (Klin. Woc henschr. 67 (1989) 106-109) was combined with immunoabsorption by diff erent monoclonal antibodies directed against pancreatic phospholipase A2. Pancreatic phospholipase A2 was purified from human duodenal juice . Monoclonal antibodies were prepared by fusion of spleen cells from i mmunized mice with P3X63-Ag8-653 myeloma cells. Samples with phospholi pase A2 activity were incubated in monoclonal antibody-coated microtit re plates. Phospholipase A2 activities were determined in the monoclon al antibody-treated samples as well as in control samples. The method allows the determination of the fraction of human phospholipase A2 iso enzymes in various biological materials. For pancreatic phospholipase A2 the specific binding capacity was about 60-80%, the unspecific bind ing was 5-30%. Practically no crossreactivity was seen with partially purified serum phospholipase A2, With recombinant platelet phospholipa se A2, or with the sera of patients with non-pancreatic diseases. In c onclusion, the present study confirmed the presence of pancreatic phos pholipase A2 in human duodenal juice and in the ascites of necrotizing pancreatitis. However, pancreatic isoenzyme was absent in non-pancrea tic inflammatory diseases. Therefore, elevated phospholipase activitie s in non-pancreatic inflammatory diseases cannot be attributed to the pancreas.