Mononuclear phagocytes of mice hyperimmunized with live vaccine of Salmonella enteritidis inhibited intracellular multiplication of a virulent strain of the same organisms, and resisted cell degeneration by bacteria, regardless of the presence of antibody in cell culture system. This cellular resistance which was referred to as cellular immunity, was transferable to mononuclear phagocytes of normal mice by Transfer Agent in vitro.
To elucidate the mechanism cf cellular immunity which was conferred by TA, the time for the induction of cellular immunity by TA, minimum effective amount of TA, and the effects of actinomycin-D and of puromycin on TA endowing cellular immunity to non-immune monocytes were studied. Following results were obtained.
1) The minimum effective amount of TA was 100 μg/ml.
2) The time for induction of cellular immunity by TA was more over 48 hrs.
3) When the normal mononuclear phagocytes were treated with TA and actinomycin-D simultaneously, the cells acquired the ability to inhibit the intracellular multiplication of bacteria, whereas, when the cells were treated with TA and puromycin, the cells did not.
It was suggested from these findings that protein synthesis but no DNA-depeadent RNA synthesis in cells was necessary for the establishment of the anti-infectious immunity of cells treated with TA in experimental salmonellosis.