Abstract
Anti-infection immunity against cytophilic bacteria such as Mycobacteria, Salmonella and Listeria depends on cellular immunity and can be induced by the inoculation of an attenuated live vaccine but not by the inoculation of a killed or component vaccine. In this study, we analyzed mechanisms of inducing anti-infection immunity against cytophilic bacteria using an experimental model of mouse Salmonellosis and examined the use of this system for the treatment of tumor-bearing mice.
Our results suggest that bacterial antigen binds to stress protein (heat shock protein : HSP), which is newly produced in macrophages after stimulation with live bacteria, and the resulting antigen-HSP complex stimulates antigen-presenting cells (APC) to produce IL12p70, leading to the development of type 1 helper T (Th 1) cells and the induction of cellular immunity.
An anti-tumor effect was observed in metastatic tumor-bearing mice after inoculation wily : live attenuated Salmonella, especially when a combined treatment of a small dose of anti-cancer agent and live Salmonella was used.
