Modified allogeneic immunity to Ehrlich ascites tumor with bacterial endotoxin [boivin's antigen] in mice

ABSTRACT

Allogenic immunity of young adult Swiss albino mice to their residual intraperitoneal tumors after aspiration of their initial ehrlich ascites tumor allografts 12 days post-implantation maintained these mice in complete remission for the rest of their lives.Yet, this solid resistance was depressed when 100 nanogram [ng] amounts of an endotoxinpreparation[Boivin'santigen] wasadministrated subcutaneously three times per week post-aspiration. Ascites tumors relapsed and developed rapidly in the allogenic hosts treated with endotoxin.On the other hand,administration of the endotoxin subcutaneously in ng amounts three times per week starting 24hours after intraperitoneal implantation of the ascites tumor heightened the resistance of the host to its tumor allograft for a week. This was marked by a delayed onset [seven days] and a slower growth rate than the controls.Such resistance was not observed when endotoxin was administrated in higher [10 and 100 ng] or lower [0.1 ng] doses. When endotoxin was administrated subcutaneously in amounts of 0.1 or 100 ng three times per week starting 12 days prior to the intraperitoneal implantation of the tumor allograft, no resistance was observed.The highest dose [100 ng] of the endotoxin had practically no effect on ehrlich ascites tumor cells after an in vitro incubation for one hour when the cells were inoculated back into normal young adult mice, except for a delay of 48 hours in the onset of the ascites tumor. The possibleuseofsystemicadjuvants of immunity in clinical immunotherapy of cancer patients conditioned by such factors as the dose and time of administration in relation to the amount of residual cancer left from a previous treatment was discussed