Studies on immunity of experimental typhoid Mechanism of the clearance of bacteria in the peritoneal cavity of mice passively immunized with antiserum

Abstract

It was observed, in the previous report, that when a certain number of virulent organisms of Salmonella enteritidis were challenged intraperitoneally into mice passively immunized with anti-O serum, a rapid clearance of bacteria occured which seemed to be caused by phagocytosis in the peritoneal cavity. Further detailed conditions for the local clearance phenomenon were investigated with the following results.1. When the immune mice were challenged intraperitoneally with a large number of more than 5×10-1mg Salmonella enteritidis, the clearance phenomenon was not recognized.2. An intraperitoneal inoculation of 5×10-1mg heat-killed bacteria of either hemologous species before challenge of the immune mice led to an abrupt reduction in the number of local phagocytes followed by a cessation of the clearance phenomenon.3. When a total body x-irradiation of 600 r was given to the immune mice 4 days before challenge, the clearance in the peritoneal cavity was considerably impaired. The degree of this depression of clearance was wellcorrelated with the decrease in the number of local phagocytic cells.4. A preadministration to the immune mice of endotoxins derived from several species of gram-negative bacteria also reduced the activity of clearance. In this case the reduction of activity was, apparently, caused by an impaired function of phagocytes, since the decrease in the number of cells was not remarkable as in the case of x-irradiation.5. A temporary absorption of local complement following an intraperitoneal administration of an overwhelming dosis of sensitized sheep erythrocytes caused a marked depression of the clearance phenomenon.This result would indicate that the presence of complement, together with phagocytic cells and antibodies, was perhaps necessary for the completion of the clearance phenomenon.