Cytotoxic activity of BCG-activated macrophages against L929 tumor cells is nitric oxide-dependent

Abstract

The tumoricidal activity of activated macrophages has been attributed largely to the release of tumor necrosis factor (TNF), or to the production of reactive oxygen or nitrogen intermediates. The L929 tumor cell line (a murine fibroblast-like cell) when treated with actinomycin D (ActD) has been used to measure TNF alpha cytotoxicity. In the present study, we determined the cytotoxic activity of BCG-activated peritoneal macrophages against ActD-untreated L929 tumor cells. Furthermore, we measured the production of hydrogen peroxide (H2O2), nitric oxide (NO) and TNF by macrophages cultured in the presence or absence of L929 cells. As expected, BCG-activated macrophages produced significant amounts of H2O2 (16.0 +/- 3.0 microM), TNF (512 U/ml) and NO (71.5 +/- 3.2 microM). TNF (256 U/ml) and NO (78.9 +/- 9.7 microM) production was unchanged in co-cultures of L929 cells with BCG-activated macrophages but H2O2 production was totally inhibited. The cytotoxic activity was dependent on NO release since L-NAME (2.5, 5.0 and 10 mM), which blocks NO synthase, inhibited the killing of L929 cells. Addition of anti-TNF (20 micrograms/ml) antibodies to the cultures did not affect the tumoricidal activity of macrophages. Our results indicate that macrophage-mediated killing of L929 cells is largely dependent on NO production but independent of H2O2 or TNF release.

An In Vitro Model for the Lepromatous Leprosy Granuloma: Fate ofMycobacterium lepraefrom Target Macrophages after Interaction with Normal and Activated Effector Macrophages

“…ACT M have been shown to be cytotoxic toward tumor cells via an RNI-dependent mechanism (21,22). An alternate possibility could be the engulfment of infected target M by the effector M. Munn …”

“…However, we wondered whether or not ACT M play a role in cell turnover; there are precedents that suggest that they may. First, numerous tumor models have shown that M can act as killer cells and attack abnormal cells (17)(18)(19)(20)(21)(22). Second, immunotherapy with Th1-type cytokines in LL patients demonstrated upgrading of clinical disease in the absence of specific T cell-mediated immunity (23,24).…”

The effect of various inflammatory agents on the phagocytosis and cytokine profile of mouse and rat macrophages

“…Thioglycollate [21], casein [22,23] and carrageenan [24,25] are widely used agents to provoke aspecifi c infl ammatory responses. In addition of their infl ammatory properties, BCG [26][27][28] and NDV vaccines [29][30][31] are immunogenic by triggering more specifi c immune response against the bacteria or virus present in the vaccine. The aim of our investigations was to compare these for mice and rats respectively); thio, cells from thioglycollate-treated animals (n = 8 and 6); cas, cells from casein-treated animals (n = 9 and 8); BCG, cells from BCG-treated animals (n = 6 and 6), car, cells from carrageenan-treated animals (n = 8 and 6), NDV, cells from NDV-treated animals ( n = 12 and 10).…”

“…5, 6, Table 1). It is to be noted that a positive, but not strong correlation (R 2 = 0.7) between [23][24][25][26][27][28][29][30][31]. These data are used in this paper for the calculation of correlations between cytokine levels and enzyme expressions.…”

“…However, that study did not involve the measurements of pro-and anti-infl ammatory cytokines regulating the arginine metabolism of macrophages. In this paper, we describe a cytokine profi le for mouse and rat peritoneal macrophages previously induced by various infl ammatory challenges, including non-specifi c (thioglycollate [20,21], casein [20,22,23], carrageenan [24,25]) and immunologically specifi c (Bacillus Calmette-Guérin, BCG [26][27][28], and Newcastle Disease Virus, NDV [20,[29][30][31]) treatments. Another macrophage function, phagocytosis has also been compared in these differently challenged macrophages.…”