IMMUNOGLOBULIN-E ANTIBODIES TO PAPAYA PROTEINASES AND THEIR RELEVANCETO CHEMONUCLEOLYSIS

Study Design. Levels of four papaya cysteine proteinases were determin ed in Chymodiactin, a pharmaceutical preparation of chymopapain (EC 3. 4.22.6) used in chemonucleolysis for the treatment of sciatica. Twelve sera known to contain immunoglobulin E antibodies to Chymodiactin wer e assayed for immunoglobulin E antibodies to these enzymes. Objectives . The goal of the study was to determine what contribution each of the four proteinases makes to the allergic response that occasionally occ urs during injection of a damaged intervertebral disc with chymopapain preparations.Summary of Background Data. The occurrence of an allergi c reaction during chemonucleolysis implies prior sensitization to comp onents of the injected enzyme solution. The latex of the unripe fruit of the papaya plant Carica papaya, from which chymopapain is purified, contains another three immunologically distinct cysteine proteinases: 1)caricain (EC 3.4.22.30), 2) glycyl endopeptidase (EC 3.4.22.25), an d 3) papain (EC 3.4.22.2). Methods. A dot-blot immunoassay was develop ed to quantify each enzyme in Chymodiactin. Total serum immunoglobulin E levels and specific immunoglobulin E antibody levels to each of the four papaya cysteine proteinases were assayed by an enzyme-linked imm unoassay in 12 sera containing immunoglobulin E antibodies to Chymodia ctin. Results. Chymodiactin contained 70% chymopapain, 20% caricain, 4 % glycyl endopeptidase, and 0.1% papain. Immunoglobulin E antibodies t o all four proteinases were found in most of the 12 sera, but in varyi ng proportions. Antibodies to glycyl endopeptidase were predominant in eight sera, and the mean amounts of immunoglobulin E directed against each protein were: glycyl endopeptidase, 4.21 IU/ml; caricain, 2.9 IU /ml; chymopapain, 1.97 IU/ml; and papain, 1.39 IU/ml. Total serum immu noglobulin E levels showed little correlation with immunoglobulin E re sponses to Chymodiactin. Conclusions. The results suggested that remov al of glycyl endopeptidase and caricain from pharmaceutical preparatio ns of chymopapain may help reduce the incidence of allergic reactions during chemonucleolysis.