The Transfer of Normal and Irritated Omentums with Subsequent Streptococcus Immunity in Rabbits.

Abstract

In a recent paper 1 it was shown that if areas of granulation tissue are formed in the peritoneums of rabbits, these animals become immune to a subsequent intrapleural infection with a highly virulent hemolytic streptococcus. The intrapleural doses varied from 100 to 250 M.L.D. and successful recovery occurred in 75% of the cases. The protection appeared to be due to the migration of tissue macrophages or clasmatocytes from the peritoneal granulating areas into the pleural cavity and particularly into the subserous tissues of the diaphragmatic and parietal pleura.

The present report describes an extension of the transfer technique. A portion of the peritoneal granulating area is removed and inserted in the peritoneum of a normal rabbit. The method is as follows: A peritoneal focus of cells is built up in a rabbit by two or three intraperitoneal injections of an irritating substance, in this case a mixture of aleuronat and starch. Four days after the last injection the animal is sacrificed, and its omentum removed and carefully freed from any lumps of aleuronat which may have become adherent to it. It is then immediately inserted in the peritoneum of a normal rabbit, under complete anesthesia. An omentum of this type is at least twice normal size. Microscopically, it is found to contain many times the number cells in the normal omentum. This increase is due principally to cells of the tissue macrophage or clasmatocyte type, as may be shown in animals stained with Trypan Blue.