Increased resistance in splenectomized mice to a methylcholanthrene-induced tumour

Abstract

Summary.-Prior splenectomy increased the resistance of BALB/c mice to a syngeneic methylcholanthrene-induced ascitic tumour inoculated i.p. The survival rate of splenectomized mice was 81-60/ while those of normal and sham-operated controls were 11.5%O and 20% respectively. The effect of splenectomy, however, was seen only within the dose range of 103 to 104 tumour cells. This effect of splenectomy was abolished by the transfer to mice of serum from tumour-bearing mice, and of spleen cells from normal donors, immediately after the inoculation of tumour cells. Cellfree ascitic fluid did not abolish the effect of splenectomy. The findings suggest that there is a subpopulation of spleen cells which produces a tumour growth enhancing factor which is found in the serum of tumour-bearing mice. IN recent years, various investigatorshave shown a renewed interest in the role of the spleen in the immune response to tumours, as the spleen is a relatively rare site for metastases when compared to the rest of the reticulo-endothelial system (Willis, 1973). In vivo experiments to examine the effect of splenectomy on the behaviour of tumours used several different criteria. Thus various workers have examined the effect of splenectomy on (a) the incidence of spontaneously arising tumours (Whitmore, Salerno and Rabstein, 1972; Check et al., 1974); (b) the induction of tumours by chemical carcinogens (Cohen, Headley and Bryan, 1973;Akamatsu, 1975); (c) the incidence of spontaneouis regression of tumours (Pollack, 1971;Ferrer and Mihich, 1968); and (d) the behaviour of transplanted tumours (Moller, 1965; Sjogren, 1973, 1974). The results of these investigations suggest that although splenectomy has no effect on the incidence of spointaneous tumours, or oni the induction of tumours by chemical carcinogens, it reduces the rate of growth of transplanted tumours, and may increase the incidence of spontaneous regression of tumours. However, several criticisms may be made of these reports. The behaviour of transplanted tumours has been followed by measurement of the size of the tumour nodule, a parameter whose significance is difficult to interpret. Furthermore, the effect of splenectomy on the survival of animals with transplanted tumours has not been reported, or has found to be negligible.Using survival as the criterion, we present evidence here that prior splenectomy increases the host resistance to a transplanted tumour. We have also followed the behaviour of the transplanted tumour, by determining the rate of ascites formation and also bv tumour cell counts.

Hematological Changes in the Mice Transplanted with Methylcholanthrene-induced Fibrosarcoma

“…MCA-induced fibrosarcoma was used to investigate the role of spleen in C 3 H/HeJ mice [8,9 ] or BALB/c mice [1].…”

“…In recent years, 3-methylcholanthrene (MCA) has been applied to various species of experimental animals because of its high carcinogenic activity, and MCA-induced tumors were used in many immunological experiments in oncological studies [1,5,6,8,9,10]. The occurrence of splenomegaly [7,10] and/or granulocytosis [2] have been reported in the mice transplanted with MCA-induced tumor.…”

Infection with LDH virus alters host response to tumours

“…IN a previous study (Chang & Turk, 1977) we found that prior splenectomy protected BALB/c mice against a syngeneic methylcholanthrene-induced tumour (Meth A;Old et al, 1962) inoculated i.p. This protection occurred only when the mice were given 103-104 cells (not outside this dose range).…”

“…The level of LDH in the serum was used to Accepted 21 December 1978 indicate the presence of the virus (Table I). Mice were splenectomized, as previously described (Chang & Turk, 1977) 14 days before tumour-cell inoculation.…”

“…It is maintained in our laboratory by serial passage in BALB/c mice (Chang & Turk, 1977) and recently it was found to be carrying LDV. The tumour was freed from virus by growth for 10 days in the brains of neonatal rats (Table I).…”