Macrophage stimulation by bacterial lipopolysaccharides. I. Cytolytic effect on tumor target cells.

Abstract

Diverse stimuli induce macrophages to become nonspecifically cytotoxic for transformed cells in vitro (1). Bacterial infections of mice by Bacillus CalmetteGu~rin (BCG) 1 (2), protozoal infestations by Toxoplasma gondii or Besnoitia jellisoni (3), certain viral infections (4), and intraperitoneal inoculations of bacterial lipopolysaccharides (LPS) (5) produce macrophages that injure transformed cells in vitro. In addition, macrophages obtained directly from tumors nonspecifically lyse transformed target cells (6-9). Taken together, these data suggest a central role for stimulated macrophages both in host control of tumor cell proliferation and in the pathogenesis of the chronic inflammatory process. However, the mechanisms involved in the stimulation of macrophages, the generation of the lytic state, and the mediation of target cell injury are not understood. Recently, we and others have shown that cytolytic properties can be induced in peritoneal macrophages by using LPS (10, 11) thereby offering the prospect of examining how macrophages become stimulated, then injure tissues. The studies reported here investigate the nature of the interaction between LPS and murine macrophages that results in the generation of their capacity to kill tumor cells in a nonspecific manner. Materials and Methods Preparations of LPS.The heptose-deficient mutant from Salmonella minnesota (R595) was grown in trypticase soy broth (Baltimore Biological Laboratories, Cockeysville, Md.) under aerated conditions. Cells were harvested by centrifugation and washed twice with 0.85% sodium chloride. LPS from R595 was extracted and purified in our laboratory by Dr. D. C. Morrison using the phenol-petroleum ether-chloroform procedure of Galanos et al. (12). The water insoluble LPS extract was then sonicated and dissolved in 0.1% triethylamine. After extensive dialysis, the LPS preparation of R595 was stored at -70°C until required. LPS from Escherichia coli serotype 0111:B4 (ATCC 12015) was extracted by the phenol-water method of Westphal and Jann (13).Media and Cell Lines. Eagle's minimal essential medium (MEM) was supplemented

Differential sensitivity of two murine leukaemia sublines to cytolysis by Corynebacterium parvum-activated macrophages

“…Moreover, pre-incubating the macrophages in medium for 24 or 48 h decreased cytolysis. If the little endotoxin in our medium was responsible for rendering macrophages cytolytic, preincubation should have had the opposite effect (Doe & Henson, 1978).…”

“…The medium utsed for measuring cyto- (Doe & Henson, 1978). On the contrary, pre-incubating activated macrophages decreased their ability to kill L1210-C cells (no pre-incubation = 84 3 + 1 30o; 24h preincubation= 433 + 3 6 %; 48h pre-incubation = 25-0 + 2-2%).…”

A collection of mRNA species that are inducible in the RAW 264.7 mouse macrophage cell line by gamma interferon and other agents.

“…Macrophages can be activated by endogenous cytokines such as interferons (IFNs) (54,61,71), granulocyte/macrophage colony-stimulating factor (26), and tumor necrosis factor (61) as well as by exogenous factors such as lipopolysaccharide (LPS) (15) and muramyldipeptide (84). When activated, macrophages manifest enhanced capabilities in the presentation of antigens, phagocytosis, the killing of intracellular pathogens, and the killing of tumor cells (reviewed in reference 93).…”

Production of Macrophage Activating Factor by Human Leukemic T Cell Lines

“…These include bacterial products (lipopolysaccharide, muramyl dipeptide, glycolipids, and cell wall preparations) (3,11,14,21,41,42), complement component (4), polysaccharides (1), synthetic polymers (12,43), and the lymphocyte products, lymphokines (17,20,30). Since lymphokines are protein factors believed to be liberated in vivo from sensitized lymphocytes (22), much effort has been made to isolate and characterize these factors, mainly from murine species (20, 30).…”