Cancer research
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Both macrophages and natural killer cells have been implicated in the antimetastatic activity of maleic anhydride-divinyl ether (MVE-5). In the present study, we attempted to utilize anti-asialo-GM1 antibody and 2-chloroadenosine, agents that kill natural killer (NK) cells and macrophages, respectively, to determine the relative contribution of each effector cell type to the overall host defense. These agents were tested in the M109 lung metastasis model in syngeneic BALB/c mice, and the cytotoxic activities of both peritoneal macrophages and splenic NK cells were followed. ⋯ By Day 5 after MVE-5 treatment, 2-chloroadenosine only inhibited macrophage tumoricidal activity, and conversely, anti-asialo-GM1 antibody only inhibited NK reactivity. Despite the ability of these agents to increase survival of metastases in control animals, they only slightly abrogated the antimetastatic activity of MVE-5. Our data suggest that caution should be exercised in using these agents to discriminate macrophage and NK responses.