Effects of sodium fusidate in animal models of insulin-dependent diabetes mellitus and septic shock.

We have evaluated the effects of the novel immunosuppressant sodium fusidate (fusidin) in the non-obese diabetic (NOD) mouse and in D-galactosamine (D-Gal)-presensitized BALB/c mice challenged with the bacterial superantigen, Staphylococcus aureus enterotoxin B (SEB) or with the endotoxin, Escherichia coli lipopolysaccharide (LPS). The NOD mouse model has clinical and histoimmunological features similar to those of human insulin-dependent diabetes mellitus (IDDM). The SEB- and LPS-treated BALB/c mouse models exhibit pathogenic similarities with human septic shock conditions. In the NOD mouse, fusidin suppressed the spontaneous development of insulitis (mean inhibition 73%) and hyperglycaemia (IDDM incidence 25% versus 0%) when administered at 40 mg/kg five times weekly for 8 consecutive weeks from the fourth week of age; concurrently treated animals exhibited reduced percentages of splenic T lymphocytes. This anti-diabetogenic effect was confirmed in the accelerated model of diabetes induced in the NOD mouse with cyclophosphamide (CY) (IDDM incidence 55% versus 21-6% using dosages of fusidin from 40 to 80 mg/kg five times weekly); protection from IDDM development was achieved even when the drug (80 mg/kg/day) was first administered 7 days after CY challenge. In contrast, fusidin did not reverse hyperglycaemia when administered to CY-treated animals within 3 days of IDDM development. In the two models of septic shock, prophylactic treatment with fusidin, 80 mg/kg given three times for 2 days prior to D-Gal/SEB or D-Gal/LPS challenge, drastically reduced the lethality compared with D-Gal/buffer-treated mice. This effect may depend on the inhibitory action of fusidin on the secretion of cytokines such as interferon-gamma and tumour necrosis factor-alpha, the serum levels of which were greatly diminished in the fusidin-treated mice (mean inhibition 50-90%). These results demonstrate that fusidin may have a role in the treatment of cell-mediated autoimmune diseases and cytokine-mediated infectious diseases in humans.     

Failure of exogenously administered interferon-gamma or blockage of endogenous interleukin-4 with specific inhibitors to augment the incidence of autoimmune diabetes in male NOD mice.

Interferon (IFN)-gamma and interleukin (IL)-4 are prototypic type 1 and type 2 cytokines which are known to play pathogenetic and protective roles, respectively, in NOD mouse IDDM. The capacity of male NOD mice to produce more IL-4 and less IFN-gamma within the insulitic lesions than females has been suggested to contribute to their lower incidence of diabetes. In this study we have tested the effects of prolonged prophylactic treatment of male NOD mice with rat IFN-gamma, mouse IFN-gamma, anti-IL-4 monoclonal antibody (mAb) and recombinant murine soluble IL-4 receptor (smIL-4R) on the diabetogenic events leading to insulitis and diabetes. None of these treatments influenced spontaneous and/or cyclophosphamide-induced autoimmune diabetogenesis in male NOD mice. Control mice exhibited comparable histological signs of insulitis and incidence of diabetes to those treated with either mouse/rat IFN-gamma or specific IL-4 inhibitors. On the contrary, both clinical and histological signs of diabetes were suppressed by prophylactic treatment with anti-IFN-gamma mAb. These findings indicate that the autoimmune diathesis of male NOD mice towards IDDM cannot be augmented by manipulation of endogenous IFN-gamma or IL-4.     

Pertussigen treatment retards, but fails to prevent, the development of type I, insulin-dependent diabetes mellitus (IDDM) in NOD mice

Current evidence supports an autoimmune etiopathogenesis for Type I, insulin-dependent diabetes mellitus (IDDM) in which the pancreatic beta (beta) cell is the specific target tissue. Recently, the NOD (non-obese diabetic) mouse has become an important model for IDDM, exhibiting many of the pathological features observed in man, including a progressive pancreatic islet leukocytic inflammation referred to as insulitis. The present study was carried out to determine the efficacy of the bacterial-derived bio-product, pertussigen, to retard the progression of insulitis and thereby prevent overt diabetes. Results revealed that (1) the rapid onset of IDDM in female NOD mice is absent if the mothers are treated with pertussigen prior to mating, (2) treatment of young prediabetic NOD mice with repeated injections of pertussigen results in the retardation of onset of IDDM when compared to untreated control NOD mice, and (3) the severity of insulitis in pertussigen-treated NOD mice not developing IDDM was noticeably less severe than age and sex-matched untreated control mice. Since earlier work had shown that pertussis vaccine, which contains pertussigen, could prevent development of IDDM in mice treated with streptozotocin, the present results may indicate basic differences in the inflammatory responses in the genetically-predisposed NOD mice and IDDM-nonsusceptible mice with streptozotocin-induced diabetes.     

Prevention of cyclophosphamide-induced diabetes in the NOD/WEHI mouse with deoxyspergualin

Ten out of 20 (50%) 17-week-old female NOD/WEHI mice developed an acute form of autoimmune diabetes when injected with two large doses of cyclophosphamide (CY), given at 14-day intervals. If these mice were treated under a prophylactic regimen with 2·5 mg/kg body weight per day of the novel immunosuppressant deoxyspergualin (DSP) the onset of diabetes was completely prevented. Moreover, DSP-treated animals showed reduced signs of pancreatic insulitis, had lower percentages of splenic lymphoid cells (SLC) expressing IL-2 receptors and Ly-6C antigens on their surfaces, and these cells released lower amounts of interferon-gamma (IFN) when stimulated in vitro. These data, providing evidence for the capacity of DSP to protect NOD/WEHI mice from experimental autoimmune diabetes and to modulate histo-immunological pathogenic pathways, indicate DSP as a drug of potential interest in the treatment of human insulin-dependent diabetes mellitus.     

IL－2对NOD鼠糖尿病的影响

ＮＯＤ鼠是人类胰岛素依赖型糖尿病的动物模型，其发病与自身免疫有关。环磷酰胺（ＣＰ）可以加速这一过程，使ＮＯＤ鼠糖尿病的发病率提高或提前。一些研究表明：ＮＯＤ鼠的淋巴细胞在淋巴细胞混合反应中（ＭＬＲ），在有或无刺激物的存在下，白细胞介素２（ＩＬ－２）的产量均明显低于正常鼠的淋巴细胞。该实验对注射了一次大剂量的ＣＰ（３００ｍｇ／ｋｇ体重）后的ＮＯＤ鼠试用了ＩＬ－２治疗。结果显示：对于年幼的ＮＯＤ鼠ＩＬ－２治疗１４无可以明显减轻注射ＣＰ后的胰岛破坏加速。病理检查显示三组胰岛炎严重程度积分分别为２９；８１；８８。ＩＬ－２处理组明显低于ＣｏｎＡ处理组与对照组。这个研究还显示，对于１２周龄的ＮＯＤ鼠，经１４天的ＩＬ－２治疗，可以完全预防ＣＰ诱导的糖尿病的发生。糖尿病发病率在ＩＬ－２组为０／１２；对照组为７／１２。但对已发病的ＮＯＤ鼠自发性糖尿病ＩＬ－２不能使其缓解。     

Islet-infiltrating T cell clones from non-obese diabetic mice that promote or prevent accelerated onset diabetes

In humans and non-obese diabetic mice (NOD), insulin-dependent diabetes mellitus (IDDM) results from a spontaneous T cell-dependent autoimmune destruction of the insulin-producing pancreatic beta cells. Previous data suggest that a delicate balance between autoaggressive T cells and suppressor-type immune phenomena determine whether expression of autoimmunity is limited to insulitis or progresses to IDDM. To resolve the cellular basis of this intricate network of pathogenic CD4+ and CD8+ T cells and the role of T cells in suppressive immune phenomena. T cell clones were propagated directly from islets of NOD mice at the onset of insulitis. Insofar as insulitis, but not IDDM, is universal in NOD mice, we have screened for the in vivo effects of the islet-infiltrating T cell clones upon expression of IDDM, not insulitis. A CD4+ T cell clone, IS-3S7D, proliferates in response to islet antigen(s) and its transfer into prediabetic NOD mice promotes the rapid onset of IDDM. An interleukin 2 (IL 2)-dependent noncytolytic, V beta 11+ CD8+. T cell clones IS-2.15, prevents an accelerated onset diabetes in two distinct models. The present study, which documents the presence of CD4+ diabetogenic T cell clones and CD8+ T cell clones that dampen autoimmunity, gives tangible evidence that opposing autoimmune processes may determine whether an autoimmune-prone host develops frank disease.     

Anti-suppressor effect of cyclophosphamide on the development of spontaneous diabetes in NOD mice

In the NOD mouse, an autoimmune process beginning by 5 weeks of age with lymphocyte infiltration and destruction of insulin-secreting beta cells leads to overt diabetes which begins to appear by 11 weeks of age. Although there is a high incidence of insulitis by 10 weeks of age (greater than 80%) in both males and females, by 30 weeks of age diabetic symptoms have occurred in 53-80% of females and in 12-40% of males. Intraperitoneal injection of a high dose (200 mg/kg) of cyclophosphamide (CY) consistently induces the onset of diabetes in male and female NOD mice at an age when spontaneous diabetes rarely occurs. Spleen T cells from CY-induced diabetic mice are capable of transferring the disease into irradiated nondiabetic syngeneic recipients. This indicates that the diabetogenic effect of CY is not mediated by direct toxicity on pancreatic beta cells but is mediated by abrogation of a suppressor mechanism which may prevent activation of T cells responsible for the development of diabetes in the NOD mouse. Additionally, CY is only effective in NOD mice and not in F1 hybrids between NOD and other strains of mice. Thus, the potential beta cell aggressor mechanism is not present in these hybrids as it is in homozygous mice, which indicates that it is not under the control of dominant genes.     

Rapamycin prevents the onset of insulin-dependent diabetes mellitus (IDDM) in NOD mice.

The effect of the immunosuppressive agent rapamycin (RAPA) was assessed in the non-obese diabetic (NOD) mouse which is an autoimmune model of IDDM. RAPA was prepared in a vehicle of 8% cremophor EL/2% ethanol and investigated in two studies. NOD/MrK female mice (six per group, study no. 1; 10 per group, study no. 2) were dosed three times per week p.o. by gavage from 56 to 170 days of age (study no. 1) or from 64 to 176 days of age (study no. 2). Mice treated with RAPA at 0.6 mg/kg, 6 mg/kg, or 12 mg/kg maintained normal plasma glucose through 170 or 176 days of age with 10%, 0%, and 0% incidence of diabetes respectively. In contrast, naive, vehicle-treated, or RAPA 0.06 mg/kg-treated mice exhibited elevated plasma glucose and disease incidence typical for female NOD mice. Mice which became diabetic had elevated levels of beta-hydroxybutyrate, triglycerides and cholesterol. These plasma lipid concentrations were positively correlated with the duration of hyperglycaemia (r = 0.85, 0.87 and 0.84 respectively). Outside of its ability to prevent diabetes, RAPA itself did not affect the lipid profile of the mice. Intervention therapy with RAPA was ineffective at reversing the course of disease after IDDM onset under these experimental conditions. Finally, we report here that prophylactic treatment with RAPA was able to protect against IDDM development in some RAPA-treated mice 41 weeks after cessation of treatment. These data show that orally administered RAPA is effective in preventing onset of disease in the NOD mouse, a relevant model of autoimmune type I diabetes in man.     

Targeting JAK3 with JANEX-1 for prevention of autoimmune type 1 diabetes in NOD mice

Here we show that Janus kinase (JAK) 3 is an important molecular target for treatment of autoimmune insulin-dependent (type 1) diabetes mellitus. The rationally designed JAK3 inhibitor JANEX-1 exhibited potent immunomodulatory activity and delayed the onset of diabetes in the NOD mouse model of autoimmune type 1 diabetes. Whereas 60% of vehicle-treated control NOD mice became diabetic by 25 weeks, the incidence of diabetes at 25 weeks was only 9% for NOD females treated with daily injections of JANEX-1 (100 mg/kg/day) from Week 10 through Week 25 (P = 0.007). Furthermore, JANEX-1 prevented the development of insulitis and diabetes in NOD-scid/scid females after adoptive transfer of splenocytes from diabetic NOD females. Chemical inhibitors such as JANEX-1 may provide the basis for effective treatment modalities against human type 1 diabetes. To our knowledge, this is the first report of the immunosuppressive activity of a JAK3 inhibitor in the context of an autoimmune disease.     

Prevention of diabetes in NOD mice treated with antibody to murine IFN gamma

The NOD mouse is studied as an animal model of human insulin-dependent diabetes mellitus (IDDM). To evaluate the role of IFN gamma in the pathogenesis of the disease, we have studied the effect of anti-IFN gamma mAb on the expression of insulitis and clinical diabetes. Treatment of mice with anti-IFN gamma mAb prevented the induction of early IDDM by cyclophosphamide as well as the adoptive transfer of diabetes by spleen cells from diabetic NOD mice. The protection against induction of diabetes by cyclophosphamide was observed in animals treated with the anti-IFN gamma mAb within 24 h following the first cyclophosphamide injection but not in animals in which mAb treatment was started 7 days later. Transfer of disease was prevented both in adult irradiated and in newborn recipients. The absence of clinical signs in these mice was corroborated by a significant reduction of both the extent and severity of insulitis. Over-expression of Ia antigen on endothelial cells lining the islets was also considerably reduced in mice treated with mAb. These data strongly suggest a role for IFN gamma during the autoimmune process leading to beta cell destruction in diabetes and prompt further investigation of the use of such antibodies in the immunoprevention of IDDM.     

Genetic and immunological basis of autoimmune diabetes in the NOD mouse

The non-obese diabetic (NOD) mouse is an animal model of human insulin-dependent diabetes mellitus (IDDM). Most NOD mice show insulitis at several weeks of age, and 60-90% of the female mice develop overt diabetes after 20-30 weeks of age. NOD mice share many features of human IDDM. As in human IDDM, the disease development in NOD mice is controlled by a number of disease susceptibility or resistant genes (Idds), including the major histocompatibility complex locus. Cumulative evidence suggests that Thl CD4+ T cells play a critical role in the autoimmune process leading to beta cell destruction. In addition to CD4+ T cells, CD8+ cells and B cells also participate in the pathogenesis. There are several candidate antigens recognized by autoreactive T cells such as glutamic acid decarboxylase (GAD), insulin and heat shock protein (HSP) 60. Treatment by these antigens suppresses IDDM development in NOD mice, suggesting that they may initiate the autoimmune process of NOD mice.     

Interleukin 2 receptor targeted fusion toxin (DAB486-IL-2) treatment blocks diabetogenic autoimmunity in non-obese diabetic mice.

Insulin-dependent diabetes mellitus (IDDM) is strikingly similar in the non-obese diabetic (NOD) mouse and humans. In IDDM, the systematic autoimmune destruction of insulin-producing beta cells within the pancreas is dependent on autoreactive T cells. This autoimmune process can be accelerated by transferring spleen cells from diabetic donors into irradiated syngeneic NOD mice. In a previous study we established that interleukin 2 receptor (IL 2R)-bearing cells propagated from pre-diabetic NOD mice promote IDDM. Therefore, we reasoned that specific elimination of IL 2R+ T cells should abort the diabetogenic process. T cell expressing IL 2R can be selectively destroyed with a diphtheria toxin-related IL 2 fusion protein (DAB486-IL-2). We set DAB486-IL-2 the challenging task of preventing fulminant IDDM accelerated by the adoptive transfer of diabetic spleen cells. Eight weeks after the adoptive transfer only 10% and 20% of NOD mice treated with 10 and 5 micrograms/day of DAB486-IL-2, respectively, became diabetic while 100% control mice (vehicle buffer) became diabetic within 5 weeks. A dose of 1 microgram/day of DAB486-IL-2 had no protective effect. Although the protection conferred by DAB486-IL-2 is not permanent, it is maintained for at least 4 weeks following cessation of treatment. Furthermore, even though these NOD mice do eventually become diabetic, the tempo of expression and severity of diabetes, as assessed by the level of hyperglycemia, is dramatically reduced. Although histologic examination of pancreas revealed minimal degree of mononuclear infiltrate within the islets in both groups, the vehicle control mice had fewer islets per section indicating many islets had already been destroyed. In addition, spleen cells from diabetic NOD mice which were pre-treated with DAB486-IL-2 (10 micrograms/day) for 1 week lost their ability to transfer disease. Taken together, these studies strongly support the concept that IL 2R-bearing T cells are essential for the induction of IDDM and suggest that DAB486-IL-2 would be a promising therapeutic approach in the treatment of human IDDM.     

G-CSF treatment prevents cyclophosphamide acceleration of autoimmune diabetes in the NOD mouse

Cyclophosphamide (CY) accelerates autoimmune diabetes in the NOD mouse at different levels, including critical targeting of a regulatory T cell subset, exacerbation of pro-Th1 IFN-gamma production and promotion of inflammation in pancreatic islets. Here we evaluated the ability of G-CSF to antagonize the acceleration of the disease induced by CY. Human recombinant G-CSF, administered daily at 200 microg/kg by s.c. injection, protected NOD mice from CY-accelerated onset of glycosuria and insulitis. G-CSF accelerated the recovery of the T cell compartment after the depletion of the lymphoid compartment triggered by CY injection. It selectively prevented the loss of the immunoregulatory T cells expressing the CD4(+)CD25+ phenotype that also stained CD62L+ in peripancreatic lymph nodes and promoted their expansion in the spleen. In addition to this, it abrogated the robust cytokine--particularly IFN-gamma- and chemokine burst triggered in immune cells by CY. G-CSF promoted only slight changes in the inflammatory effects of CY at the target tissue site, assessed by chemokine induction within the pancreas. Thus the immunoregulatory properties of G-CSF were critical in the early control of the accelerating effects of CY on autoimmune diabetes in the NOD mouse.     

The effect of bone marrow and thymus chimerism between non-obese diabetic (NOD) and NOD-E transgenic mice,on the expression and prevention of diabetes

The non-obese diabetic (NOD) mouse is an established animal model of the autoimmune disease, insulin-dependent diabetes mellitus (IDDM). The NOD-E mouse is a transgenic mouse which expresses the I-E molecule (absent in NOD mice). Expression of I-E protects these mice from both insulitis and IDDM.We have investigated the possible mechanisms of this protection by constructing bone marrow, and combined bone marrow and thymus chimeras between NOD and NOD-E mice. Our data suggest that thymic epithelium may play no direct role in either protection against, or promotion of, IDDM. Protection from diabetes is provided either by NOD-E donor bone marrow or NOD-E recipient non-thymic radioresistant cells. The means by which protection may be achieved in this system are discussed.     

Acceleration of autoimmune diabetes by cyclophosphamide is associated with an enhanced IFN-gamma secretion pathway

Cyclophosphamide (CY), an alkylating cytostatic drug, is known for its ability to accelerate a number of experimental autoimmune diseases including spontaneous diabetes in NOD mice. The mechanism(s) by which CY renders autoreactive lymphocytes more pathogenic is largely unknown, but it has been postulated that the drug preferentially depletes regulatory (suppressor) T cells. It has been suggested that in cell-mediated autoimmune diseases, Th2-like lymphocytes secreting IL-4 and/or IL-10 provide protection, while Th1-like cells secreting IFN-gamma are pathogenic. In this study, we analysed the effects of CY on autoimmune diabetes and cytokines in two mouse models: the spontaneous diabetes of NOD mice and the diabetes induced in C57BL/KsJ mice by multiple injections of low dose streptozotocin (LD-STZ). In both models, CY induced severe lymphopenia and accelerated the progression to hyperglycemia. This was associated with changes in splenic cytokine patterns indicating a shift towards the IFN-gamma-secreting phenotype. We provide here evidence that IFN-gamma producers are relatively resistant to depletion by CY and that Th0 clones can be shifted towards Th1. However, direct exposure of T lymphocytes to CY may not be a necessary condition for exacerbation of diabetes; NOD.scid mice treated with CY before adoptive transfer of NOD splenocytes developed diabetes at a higher rate than did controls. Thus, the acceleration of diabetes by CY seems to be a complex event, which includes the relatively high resistance of IFN-gamma producers to the drug, their rapid reconstitution, and a Th1 shift of surviving T cell clones.     

Enhanced metabolism of arachidonic acid by macrophages from nonobese diabetic (NOD) mice.

The inbred nonobese diabetic (NOD) mouse spontaneously develops an autoimmune diabetes, which is now recognized as an experimental model for human type I insulin-dependent diabetes mellitus (IDDM). The autoimmune reaction, specifically directed against pancreatic beta cells (insulitis), involves both macrophages and T lymphocytes. The study of the production of cyclooxygenase and lipoxygenase derivatives of arachidonic acid metabolism shows that in some conditions, and in particular in the presence of zymosan A, macrophages from NOD mice produced significantly more 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and leukotriene C4 (LTC4) than macrophages from age- and sex-matched C57BL/6 mice. Moreover, zymosan A-stimulated macrophages from NOD females produced significantly more LTC4 than did macrophages from NOD males. These results may be of interest, given the bidirectional relationship between the various cytokines involved in the destruction of beta cells of the islets of Langerhans and different eicosanoids.     

Inhibition of diabetes in NOD mice by idiotypic induction of SLE.

The present study was undertaken to investigate whether active induction of systemic lupus erythematosus (SLE) in non-obese diabetic (NOD) mice could affect their development of insulin-dependent diabetes mellitus (IDDM). NOD mice were immunized with a human IgM mAb carrying the 16/6 idiotype (MIV-7) or with control human IgM. The mice were bled monthly and tested for SLE-associated autoantibodies in the serum and for the presence of leukopenia, thrombocytopenia, proteinuria and immunoglobulin deposits in the kidneys. The development of diabetes was determined by a blood glucose level exceeding 15 mM on two consecutive weekly determinations and by the presence of insulitis in the pancreas. The NOD mice immunized with MIV-7 developed high and persistent levels of autoantibodies, including anti-DNA, anti-histones and anti-cardiolipin, untreated mice and those immunized with normal human IgM did not produce these autoantibodies. The MIV-7-immunized mice also manifested an elevated erythrocyte sedimentation rate, leukopenia, thrombocytopenia and significant proteinuria, as well as deposits of Ig in their kidney glomeruli. Thus, NOD mice immunized with MIV-7 developed both autoantibodies and clinical features of SLE. The MIV-7-treated mice, however, showed a significantly lower incidence of IDDM (25%vs. 90%, P<0.003), accompanied by amelioration of the insulitis. The present study indicates that the induction of SLE by idiotypic immunization can protect NOD mice from developing IDDM, pointing to the importance of immune dysregulation in shift from one autoimmune disease to another.     

AEB-071 has minimal impact on onset of autoimmune diabetes in NOD mice

Protein kinase C (PKC) is an important signaling enzyme in the activation and regulation of T lymphocytes. T-cell-mediated destruction of β-cells is a characteristic feature of autoimmune (Type 1) diabetes. Here we explore the ability of PKC inhibition, using the PKC inhibitor AEB-071 (AEB), to reduce disease in two animal models of spontaneous autoimmune diabetes (non-obese diabetic (NOD) mouse and biobreeding rat (BB)). NOD mice were treated with AEB for 4 weeks, starting at either 4 weeks of age (prior to the development of insulitis) or at 8 weeks of age, once insulitis is present. Animals treated with AEB during the effector phase of the disease (treatment onset at 8 weeks of age), showed a 2-week delay in diabetes onset (p < 0.05). In these animals, the extent of insulitis was lower than in vehicle-treated controls; however, neither serum autoimmune anti-GAD65 antibody levels nor pancreatic insulin content were different between experimental groups. Overall, inhibition of PKC can mildly reduce lymphocytic infiltrate of pancreatic islets and modestly delay onset of autoimmune diabetes in NOD mice. AEB, a T-cell-targeted immunosuppressive strategy, is only sufficient as a monothereapy to modestly delay onset of autoimmune disease in the NOD mouse.     

Acceleration of Autoimmune Diabetes by Cyclophosphamide is Associated with an Enhanced IFN-γ Secretion Pathway

Cyclophosphamide (CY), an alkylating cytostatic drug, is known for its ability to accelerate a number of experimental autoimmune diseases including spontaneous diabetes in NOD mice. The mechanism(s) by which CY renders autoreactive lymphocytes more pathogenic is largely unknown, but it has been postulated that the drug preferentially depletes regulatory (suppressor) T cells. It has been suggested that in cell-mediated autoimmune diseases, Th2-like lymphocytes secreting IL-4 and/or IL-10 provide protection, while Th1-like cells secreting IFN-γ are pathogenic. In this study, we analysed the effects of CY on autoimmune diabetes and cytokines in two mouse models: the spontaneous diabetes of NOD mice and the diabetes induced in C57BL/KsJ mice by multiple injections of low dose streptozotocin (LD-STZ). In both models, CY induced severe lymphopenia and accelerated the progression to hyperglycemia. This was associated with changes in splenic cytokine patterns indicating a shift towards the IFN-γ-secreting phenotype. We provide here evidence that IFN-γ producers are relatively resistant to depletion by CY and that Th0 clones can be shifted towards Th1. However, direct exposure of T lymphocytes to CY may not be a necessary condition for exacerbation of diabetes; NOD.scid mice treated with CY before adoptive transfer of NOD splenocytes developed diabetes at a higher rate than did controls. Thus, the acceleration of diabetes by CY seems to be a complex event, which includes the relatively high resistance of IFN-γ producers to the drug, their rapid reconstitution, and a Th1 shift of surviving T cell clones.     

The immunosuppressant FK-506 prevents progression of diabetes in nonobese diabetic mice.

A novel immunosuppressive compound, FK-506, isolated from Streptomyces has potent immunosuppressive activities. To investigate the effect of FK-506 on the course of diabetes in nonobese diabetic (NOD) mice, we gave this drug to these animals, from the age of 8 weeks, intraperitoneally, in doses of 0.1 mg (2.5 mg/kg/day) or 0.01 mg (0.25 mg/kg/day) three times a week. Overt diabetes were observed in 75.5% of control mice by the age of 20 weeks. In contrast, no diabetes occurred in mice given 0.1 mg of FK-506. Sixteen percent of mice treated with 0.01 mg of the drug became diabetic. Administration of this drug prevented the progression of insulitis in NOD mice. The mice given 0.1 mg of FK-506 lost weight, but this was reversible.