“…It has been demonstrated that rabbit antibodies against trypsin inhibit the activity of the enzyme toward both high and low molecular weight substrates (I). Their affinity for trypsin increases with prolonged immunization and is proportional to their inhibitory capacity (10). The level of immunoreactive trypsin, which cannot be distinguished from trypsinogen by radioimmunoassay (2, 1 I), is considerably decreased in plasma of patients affected with chronic pancreatitis (9).…”