Effects of the Landschütz ascites carcinoma and ascitic fluid on macrophage activity in C. parvum-injected mice

Abstract

I.p. administration of 1.4 mg Corynebacterium parvum (C. parvum) 24 h before inoculation of Landsch├╝tz ascites carcinoma (LAC) cells significantly impaired growth of the tumour in MF1 mice. The injection of tumour cells caused a transient inhibition of the activity of the mononuclear phagocyte system (MPS) in both normal and C. parvum-treated hosts, as evidenced by impaired clearance of colloidal carbon from the bloodstream and reduction in hepatic phagocytosis of 51Cr-labelled sheep erythrocytes. Depression in Kupffer-cell activity was associated with a shift in particle distribution towards the spleen. The pronounced hepatosplenomegaly in response to C. parvum was significantly less in animals which also received tumour cells. Histological examination of liver and spleen revealed evidence of depressed MPS activity. Granuloma production in the liver in response to C. parvum was inhibited in tumour-bearing mice, and macrophage proliferation within the spleen was also reduced. Ascitic fluid showed similar inhibitory effects to those of tumour-cell suspensions, suggesting production by LAC of a heat-stable macrophage-inhibitory factor. Images Fig. 3 Fig. 4

Inhibition by the Landschütz ascites carcinoma of the granulomatous inflammatory response to C. parvum

“…In a recent study, we found that injection of Landschiitz ascites carcinoma (LAC) cells substantially reduced the increase in hepatic phagocytic activity induced by CP (McIntosh et al, 1981). Furthermore, in the same study we found that after injection of the microorganism the incidence of granulomas was markedly reduced in tumour-bearers.…”

Tumour-Induced Suppression of Delayed-Type Hypersensitivity in the Mouse: Independence of Cyclophosphamide-Sensitive Suppressor Cells

“…We have previously shown that the growing LAC and soluble tumour-associated factors suppress ma crophage activities [19] and monocyte inflammatory responses in vivo [20] and in vitro [18]. There is, how ever, no reduction in the number of circulating mono cytes associated with growth of the tumour.…”