Antibody to gastrone--endogenous inhibitor of gastric secretion.

Abstract

Antigastrone antibody was raised in rabbits by repeated injections of gastrone B obtained by Sephadex G-100 fractionation of pooled anacid human gastric juice and emulsified in Freund's adjuvant. The antigastrone antibody was an IgG by immunoelectrophoresis and formed a single precipitin arc against the material injected. Fractions obtained by Sephadex fractionation, containing the bulk of biologically active gastrone B material, gave single precipitin arcs at concentrations of 0.25 to 0.5 mg/ml by double immunodiffusion against the rabbit antigastrone sera. Fractions containing gastrone A, but devoid of gastrone B, did not react with the antibody. A single precipitin arc was also formed when pooled unfractionated anacid human gastric juices were tested against four rabbit antigastrone sera, while no precipitin lines were obtained with three normal acid human gastric juices. A total of 80 biologic assays on rats with chronic gastric fistula demonstrated the complete removal of the inhibitory activity of gastrone B solutions on gastric secretion by immune precipitation with gastrone B antibody. No effect of normal rabbit serum on the biologic activity of gastrone B was observed under similar conditions. The development of the antibody to gastrone B with no demonstrable cross-reactivity to other nondialyzable materials in human gastric juice speaks for the homogeneity of the gastrone preparation used and introduces the possibility that this antibody can be used for further study of gastrone's role in gastrointestinal physiology and pathology.