Wynn, Susan Rudd

Abstract The neutral protease tryptase has been isolated from a human mast cell line, HMC-1. The HMC-1 line was established from the peripheral blood of a patient with mast cell leukemia and maintained as continuously proliferating clones in vitro and as solid mast cell tumors in nude mice. HMC-1-derived tryptase was purified by sequential chromatography on Dowex 1, DEAE 5 PW, and heparin-agarose. Purified tryptase has an apparent molecular weight of 150,000, as determined by molecular sieve HPLC, but migrates as a doublet of bands of 32/35,000 on SDS-PAGE gels. Maximal enzymatic activity was observed at pH 8.5. Cleavage of tosyl-L-arginine methyl ester by purified tryptase was inhibited by dansyl-L-glutamyl-glycyl-L-arginine chloromethyl ketone 2 HCI, HgCI2, tosyl-L-lysine chloromethyl ketone, leupeptin, and PMSF but not by benzamidine, aprotinin, tosyl-L-phenylalanine chloromethyl ketone, soybean trypsin inhibitor, human plasma, ovomucoid inhibitor, or lima bean trypsin inhibitor. Microsequencing of purified tryptase yielded an amino terminal sequence that was identical to that previously reported for human pituitary-derived tryptase.

Follow-up survival and health information were obtained, after a median of 27.5 years, from 132 patients who had been seen originally as children with nephrotic syndrome between 1951 and 1967. Ninety seven patients were alive. Recurring edema or proteinuria, or both, persisted in 15 percent of those still alive. Eight of 11 parous women reported relapses during pregnancy. There was no apparent increase in malignancies, atopic diseases, clinical defects in cell-mediated immunity, or cardiovascular diseases. Twenty two patients (17%) died of renal causes between 3 months and 8 years after the onset of nephrotic syndrome. Steroid resistance was the presenting feature universally predictive of a poor outcome; nine of the 11 such patients died and the other two are now receiving hemodialysis. Hematuria was present initially in 41 percent of the patients who died of renal causes, compared with 14 percent of those still alive. Hypertension was noted on the first examination in 22 percent of those who died of renal causes, compared with 10 percent of those alive.