The role of cytotoxic macrophages in non-obese diabetic mice: cytotoxicity against murine mastocytoma and beta-cell lines.
The cytotoxicity of macrophages from non-obese diabetic (NOD) mice against murine mastocytoma (P-815), and murine beta-cell lines having the NOD gene background (MIN6N-9a), were examined. Peritoneal exudate cells from 20-week-old mice showed higher cytotoxicity, measured as inhibition of thymidine uptake into P-815, than those from 12-week-old mice (p < 0.01). In cyclophosphamide-injected mice, cytotoxicity of peritoneal exudate cells had increased at 8 days post-injection, at which time the mice were not diabetic. To confirm macrophage cytotoxicity against pancreatic cells and examine its cytolytic mechanism, the cytotoxicity of peritoneal exudate cells from cyclophosphamide-injected NOD mice against MIN6N-9a cells was measured by the chromium release assay. These peritoneal exudate cells showed higher cytotoxicity as compared to those of saline-injected mice (p < 0.001). Macrophages were demonstrated to be the major component of peritoneal exudate cells (50%) by flowcytometric analyses. Cytotoxicity increased with macrophage enrichment by adhesion (p < 0.01). Furthermore, a macrophage toxin, silica, completely blocked the cytotoxicity (p < 0.001). Cytokines (interleukin 1 and tumour necrosis factor) and a nitric-oxide-producing vasodilator, sodium nitroprusside, were cytotoxic to MIN6N-9a cells but only sodium nitroprusside showed cytotoxicity when incubated for the same period as peritoneal exudate cells. Thus, macrophages play an important role in beta-cell destruction and soluble factors other than cytokines (e.g. nitric oxide) may be mediators of this early cytolytic process.
Kasuga
A
A
Department of Internal Medicine, Keio University, School of Medicine, Tokyo, Japan.
Maruyama
T
T
Takei
I
I
Shimada
A
A
Kasatani
T
T
Watanabe
K
K
Saruta
T
T
Nakaki
T
T
Habu
S
S
Miyazaki
J
J
D000375:Aging / Q000276:immunology; D000818:Animals; D002460:Cell Line; D003520:Cyclophosphamide / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007515:Islets of Langerhans; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology* / Q000502:physiology; D012515:Mast-Cell Sarcoma; D051379:Mice; D008813:Mice, Inbred ICR / Q000276:immunology; D016688:Mice, Inbred NOD / Q000276:immunology*; D009569:Nitric Oxide / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013045:Species Specificity; D013936:Thymidine / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D003520:Cyclophosphamide; D004247:DNA; D013936:Thymidine