PMID: 2107257Mar 15, 1990Paper

Inhibitors of C1q biosynthesis suppress activation of murine macrophages for both antibody-independent and antibody-dependent tumor cytotoxicity

The Journal of Immunology : Official Journal of the American Association of Immunologists
R W LeuM J Herriott

Abstract

The inhibitors of C1q biosynthesis and secretion, 3,4-dehydro-DL-proline (DHP) and 2,2'-dipyridyl, were previously shown to suppress murine macrophage FcR-dependent phagocytosis and cytolysis of IgG-opsonized RBC targets. Inasmuch as non-antibody macrophage activators also bind C1q to initiate C1 activation, we determined the effects of these same inhibitors of C1q biosynthesis on activation of macrophages for antibody-independent, nonspecific tumor cytotoxicity by lipid A and a variety of other non-antibody activators. Preexposure of mouse inflammatory peritoneal macrophages to either DHP (0.5 to 2.5 mM) or 2,2'-dipyridyl (0.1 to 0.3 mM) for 24 h produced a dose-related suppression of their response to activation by lipid A to mediate tumor cytotoxicity of L1210 mouse leukemia targets. Inhibition of C1q secretion by DHP-treated macrophages was confirmed both by a complement hemolytic assay and by autoradiographic analysis of [35S]methionine-labeled culture supernatants. DHP-treated macrophages were inhibited in their response to direct activation and triggering of IFN-gamma-primed macrophages by lipid A, Poly I:C, and cobra venom factor for tumor cytotoxicity. DHP inhibited macrophage activation for antibody-dependent cellular...Continue Reading

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