Cytotoxicity of nonspecific activated macrophages

ABSTRACT

Partial resistance against Ehrlich ascites tumor [EAT] in Swiss albino mice was nonspecifically induced by single injection of a dead bacterial vaccine [i.p tumor +AD0- 90 ml/ kg body weight] rather than a living bacterial vaccine [i.p. tumor +AD0- 205 ml/ kg body weight] of the Gram- positive cocci of M. luteus, when compared to controls [i. P. tumor +AD0- 387 ml/ kg body weight]. Tumor inhibition was better noted in mice injected 4 and 7 days previously with living or dead bacteria respectively. The observed inhibition was related at least in part to the presence of activated macrophages in the peritoneum after vaccination. There was a proportional relationship between the macrophage of the i.p. tumor and the degree of inhibition+ADs- the more the inhibition the higher the content. Macrophage content was 16, 19 and 22+ACU- of total ascites cells, in mice given dead bacterial vaccine 1, 4 and 7 days previously, and developing ascites tumor measuring 330, 300 and 90 ml/kg body weight [on termination 2 weeks post i.p. tumor transplantation] respectively. A similar correlation was observed in mice given living vaccine of the same bacteria. Although these findings of the apparent inhibition of i.p. tumor could be explained on the basis of local interaction between the activated macrophages and the ascites tumor cells, the associated inhibition of sc. tumor growth in the same host at challenge the site was encouraging enough to suggest that vaccination might bring activated macrophages in contact with tumor cells at distant sites of the disease +ADs- Sc. tumor measured 3, 9, and 13 cu mm in mice injected with the dead bacterial vaccine compared to 86 cu mm in the untreated controls. Similar inhibition was observed in mice given the living bacterial vaccine