Diabetes, Vol 40, Issue 9 1210-1217, Copyright © 1991 by American Diabetes Association
Morphological analysis of selective destruction of pancreatic beta-cells by cytotoxic T lymphocytes in NOD mice
M Hayakawa, K Yokono, M Nagata, N Hatamori, W Ogawa, A Miki, H Mizoguti and S Baba
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
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.