Characterization of monoclonal islet cell reactive autoantibodies from the diabetic biobreeding (BB/OK) rat.

Two fusion experiments using the heteromyeloma cell line CB-F7 and splenocytes from two diabetes-prone BB (BioBreeding) rats at the onset of diabetes resulted in 128 islet cell reactive autoantibodies primarily detected with permeabilized insulin-producing rat insulinoma cells (RIN) by a cellular enzyme-linked immunosorbent assay. Seventy-nine (62%) of 128 RIN cell reactive supernatants exhibited a cross-reactivity with rat splenic lymphocytes. Six stable hybridomas secreting monoclonal ICSA (islet cell surface antibodies) were established, but only one monoclonal antibody, R4B10, showed preferential beta-cell binding.

Humoral-mediated cytotoxicity to rat pancreatic exocrine cells in serum of diabetes-prone BB/OK rats--predictive value for diabetes onset.

Diabetes-prone BB/OK rats were checked in a follow-up study between 40 and 200 days of age for the appearance of humoral-mediated cytotoxicity to rat pancreatic exocrine cells in serum by 51Cr-release assay. BB/OK rats maintaining normoglycaemia were characterized by a pronounced decrease of anti-exocrine cell cytotoxicity in serum at 75 and 105 days of age compared to the initial value at day 40. In contrast, in animals developing diabetes cytotoxicity was found more frequently and the level of cytotoxicity did not likewise decrease during the period up to diabetes onset.

Alterations of purine metabolism in mononuclear cell populations of first degree relatives of insulin-dependent diabetic individuals with disturbed glucose tolerance.

In a T lymphocyte and macrophage-depleted mononuclear cell population of the peripheral venous blood of 10 of 41 first degree relatives of insulin-dependent diabetic individuals who had or had had disturbed glucose tolerance adenine uptake rates were significantly increased, the relative adenine incorporation rates into the adenine nucleotides, however, were diminished. Values were compared with those of 30 controls. In 7 of 9 investigated individuals with increased adenine uptake rates antibody-dependent cellular cytotoxicity against rat Langerhans islets (ADCC) was increased in the same cell population.

Monoclonal antibody-mediated cytotoxicity against rat beta cells detected in vitro does not cause beta-cell destruction in vivo.

Two monoclonal Beta-cell surface antibodies M10H6 und K14D10 were obtained by fusion of spleen cells of Balb/c mice with the myeloma cell line P(3)0. The monoclonal antibody M10H6 was induced by immunization with rat insulinoma cells finally boostered with disintegrated rat islets, whereas the K14D10 was generated after immunization with porcine proinsulin. Both monoclonals belong to the IgG2A isotype and were screened with insulin-producing rat insulinoma cells by an indirect immunofluorescence test as well as by a cellular enzyme linked immunosorbent assay.

Immunological and beta-cell-specific characteristics of diabetes-prone BB/OK rats and their congenic derivatives--a comparative study.

In a comparative study congenic rat strains bearing either the genetic background of diabetic BB/OK rats and the MHC (RTla) of diabetes-resistant LEW.1A rats (BB.1A/OK) or vice versa carrying the genetic background of LEW.

CELISA for rapid screening of monoclonal islet cell surface antibodies using living rat insulinoma cells as target.

An improved rapid cell enzyme-linked immunosorbent assay (CELISA) is described which is suitable for the large scale screening of monoclonal antibodies to islet cell surface antigens. 5 x 10(4) insulin-producing rat insulinoma (RIN) cells were seeded per well in a 96-well flat-bottomed polystyrene plate coated one day before a 0.01% poly-D-lysine solution in PBS.

Ciamexone suppressed anti-islet ADCC of mononuclear cells and serum from type 1 (insulin-dependent) diabetic patients.

ADCC (Antibody-dependent cellular cytotoxicity) against xenogenic islets has frequently been found in newly diagnosed Type 1 (insulin-dependent) diabetics suggesting that when combined with autologous serum in vitro, the destruction of islet cells caused by mononuclear cells (MNC) reflects islet destruction in vivo. In this study the ability of Ciamexone to suppress the anti-islet ADCC in vitro was investigated. We selected both ADCC positive and ADCC negative subjects from a group of Type 1 diabetics.

Effect of lymphocytes and serum from probands before and after manifestation of type 1 (insulin-dependent) diabetes on rat islets in vitro.

In a two-year follow-up study neonatal rat islets have been shown to be affected in vitro by lymphocytes and complement-inactivated serum obtained from newly diagnosed Type 1 (insulin-dependent) diabetic patients and probands who are at high risk for developing the disease. The effect was measured by 51Cr-release of the islets treated with the proband's serum after a 6 h-incubation with lymphocytes of the same donor. Nineteen newly diagnosed diabetic patients, 23 persons at risk and 11 control probands were studied.