Morphological analysis of selective destruction of pancreatic beta-cells by cytotoxic T lymphocytes in NOD mice.
Interactions of pancreatic islets and islet-associated mononuclear cells (IAMCs) from the nonobese diabetic (NOD) mouse were morphologically investigated. To obtain IAMCs, pancreatic islets isolated from adult NOD mice were cultured for 7 days with interleukin 2. Noted by light microscopy, interactions between IAMCs and freshly isolated islets from young NOD mice began 30 min after the initiation of the coculture, and 6 h later, normal cellular array of the islets was lost. By electron microscopy, most IAMCs had low nucleus-cytoplasm ratio, the nucleus was notched and exhibited condensed chromatin along the nuclear membrane, and well-developed Golgi complexes and several mitochondria were distributed in the cytoplasm. These IAMCs adhered to beta-cells, but not to alpha- or delta-cells, with their pseudopods and caused cytolysis of beta-cells. Immunohistochemical study with antibodies specific for pancreatic hormones demonstrated that only cells reacting with anti-insulin antibody were selectively lost as the incubation time proceeded. Electron immunohistochemistry by immunogold technique showed that effector cells in IAMCs reacted with anti-CD8 (Lyt-2) antibody, but not anti-CD4 (L3T4) or anti-asialogangliosideM1 antibody. In addition, the concentration of pancreatic hormones in the culture medium, used as a marker of cytolysis, also demonstrated that insulin was significantly increased after 6 h of culture, whereas glucagon and somatostatin were not. These results suggest that CD8+ cytotoxic T lymphocytes are involved in the selective destruction of pancreatic beta-cells in the NOD mouse.
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
M
M
Hayakawa
K
K
Yokono
M
M
Nagata
N
N
Hatamori
W
W
Ogawa
A
A
Miki
H
H
Mizoguti
S
S
Baba
D000818:Animals; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D005260:Female; D005934:Glucagon / Q000032:analysis; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis; D007515:Islets of Langerhans / Q000276:immunology* / Q000473:pathology / Q000648:ultrastructure; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D008817:Mice, Mutant Strains; D008854:Microscopy, Electron; D013004:Somatostatin / Q000032:analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D007328:Insulin; D013004:Somatostatin; D005934:Glucagon