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Some requirements for the secretion of tumour necrosis factor and its cytotoxic activity in vitro
V Danielová1, J Holubová, J Sourek
1Institute of Hygiene and Epidemiology, Praha.
Abstract:
The bacterial lipopolysaccharide (LPS) in vitro-induced secretion of tumour necrosis factor (TNF) by mouse macrophages is described. The highest amount of TNF was produced by DBA/2 mouse peritoneal macrophages activated by a dose of 1 microgram LPS for 3 h. The yield of TNF was higher in the presence of indomethacin during LPS induction. A markedly positive effect on TNF yield of the priming of macrophages in vivo was manifested by proliferation of peritoneal macrophages and increased secretion of TNF as well. No significant effect of hyperthermia (41 degrees C) on TNF secretion could be found. At 41 degrees C, however, TNF cytotoxic activity against the tumour L-929 mouse cells was considerably increased and accelerated, even in the absence of actinomycin D. The maximum cytotoxic activity with or without actinomycin D was reached 15 h later, and it significantly exceeded the value obtained at 37 degrees C at 20 h in the presence of actinomycin D; in the absence of the latter the maximum cytotoxic activity was reached in more than 48 h at 37 degrees C.
Insights
Bacterial lipopolysaccharide (LPS) stimulates mouse macrophages to secrete tumor necrosis factor (TNF). Indomethacin and in vivo priming enhance TNF yield, while hyperthermia increases its tumor cell activity.
Area of Science:
- Immunology
- Cell Biology
Background:
- Tumor necrosis factor (TNF) is a key cytokine in inflammatory responses.
- Bacterial lipopolysaccharide (LPS) is a potent activator of macrophages.
Purpose of the Study:
- To investigate factors influencing TNF secretion and activity by mouse macrophages.
- To evaluate the effects of indomethacin, in vivo priming, and hyperthermia on TNF production and function.
Main Methods:
- In vitro induction of TNF secretion from mouse peritoneal macrophages using LPS.
- Assessment of TNF yield under varying conditions, including the presence of indomethacin.
- Evaluation of macrophage priming in vivo.
- Analysis of TNF cytotoxic activity against L-929 tumor cells at different temperatures (37°C and 41°C) with and without actinomycin D.
Main Results:
- DBA/2 mouse peritoneal macrophages produced maximal TNF with 1 microgram LPS after 3 hours.
- Indomethacin and in vivo priming (macrophage proliferation) significantly increased TNF yield.
- Hyperthermia (41°C) did not affect TNF secretion but markedly increased and accelerated its cytotoxic activity against L-929 cells, even without actinomycin D.
Conclusions:
- LPS is an effective inducer of TNF secretion in mouse macrophages.
- Modulating factors like indomethacin and in vivo priming can enhance TNF production.
- Hyperthermia potentiates TNF's cytotoxic effects on tumor cells, suggesting a potential therapeutic avenue.