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Interferon-mediated protection of B16 melanoma cells from cytotoxicity by activated macrophages
Abstract:
Corynebacterium parvum-activated macrophages (M phi), purified by adherence, were cytotoxic for B16 melanoma cells maintained in vitro. Pretreatment of the melanoma cells for 18 hr with interferon-alpha/beta or -gamma (IFN-alpha/beta or -gamma) caused a reduced susceptibility of the B16 cells to M phi-mediated cytotoxicity. The IFN-induced protective effect of B16 cells from cytotoxic M phi was found to be dose dependent. In addition, IFN-gamma was more protective than IFN-alpha/beta. The protective effect observed with partially purified IFN was reproduced by using highly purified IFN-alpha/beta or recombinant IFN-gamma. Monoclonal antibodies to IFN-gamma neutralized the protective effect provided by IFN-gamma. These results show that the susceptibility of a tumor cell line to killing by activated M phi can be altered by IFN pretreatment.
Insights
Interferons (IFN) protect B16 melanoma cells from macrophage-mediated cytotoxicity. This protective effect was dose-dependent, with IFN-gamma showing greater efficacy than IFN-alpha/beta, indicating IFNs can alter tumor cell susceptibility to immune attack.
Area of Science:
- Immunology
- Cancer Biology
- Cellular Cytotoxicity
Background:
- Activated macrophages (M phi) exhibit cytotoxic activity against tumor cells.
- Tumor cells can modulate their susceptibility to immune-mediated killing.
Purpose of the Study:
- To investigate the effect of interferon (IFN) pretreatment on the susceptibility of B16 melanoma cells to macrophage-mediated cytotoxicity.
- To compare the protective efficacy of different types of IFNs.
Main Methods:
- B16 melanoma cells were pretreated with various concentrations of interferon-alpha/beta or interferon-gamma.
- Cytotoxicity was assessed by co-culturing treated melanoma cells with Corynebacterium parvum-activated macrophages.
- Monoclonal antibodies against IFN-gamma were used to neutralize its protective effect.
Main Results:
- Interferon pretreatment significantly reduced the susceptibility of B16 melanoma cells to macrophage-mediated killing.
- The protective effect of IFNs was dose-dependent.
- Interferon-gamma demonstrated a greater protective effect compared to interferon-alpha/beta.
- Neutralization with anti-IFN-gamma antibodies abolished the protective effect of IFN-gamma.
Conclusions:
- Interferon pretreatment can alter tumor cell susceptibility to activated macrophage cytotoxicity.
- IFN-gamma is a potent modulator of tumor cell resistance to immune attack.
- These findings highlight the potential of IFNs in modulating anti-tumor immune responses.