Some Immunological Studies with Heat-Denatured Bovine Serum Albumin and Its Peptic,Tryptic,and Chymotryptic Peptides 1

Abstract

Summary

The effect on passive anaphylaxis and delayed hypersensitivity in guinea pigs and immune tolerance in rabbits of injections of heat-denatured bovine serum albumin (HDBSA) and its dialyzable and non-dialyzable peptides, formed by the action of crystalline trypsin, chymotrypsin, and pepsin has been presented. In some experiments, a comparison has been presented with the effect of native bovine serum albumin (BSA). A direct relationship was observed between the molecular size of the peptides and their in vivo immunological activities. There were also some differences in the immunological activity of peptides formed by the different enzymes. Chymotryptic peptides were most effective in eliciting passive anaphylaxis; whereas, there were no significant differences in the ability of nondialyzable products of various enzymes in causing Arthus and delayed hypersensitivity reactions in guinea pigs. Heat denaturation did not affect the ability of BSA to cause Arthus and delayed reactions. In fact, HDBSA and BSA behaved very similarly and also cross reacted equally well in the above reactions. Dialyzable peptides produced some Arthus reactions but no delayed reactions, whereas nondialyzable peptides elicited good Arthus reaction and some delayed hypersensitivity. Under the conditions in which tolerance to BSA was induced in rabbits, neither HDBSA nor its tryptic digests were able to establish complete tolerance in rabbits.