Immunotherapy of the nonobese diabetic mouse: treatment with an antibody to T-helper lymphocytes

Strategies in immunotherapy of insulin-dependent diabetes mellitus

Complete and definitive prevention of diabetes obtained in animal models by using a number of diversified maneuvers has elicited major hope for immunoprevention of the disease in man. Therapeutic trials of immunosuppressive drugs in human IDDM have opened the way towards prevention or cure of the disease. Difficulties encountered, including requirement for chronic immunosuppression and risk of metabolic relapses, suggest two complementary approaches: precocious intervention based on early and reliable disease prediction, and tolerance-inducing regimens, hopefully using shorter and innocuous therapy. Animal data suggest that this is indeed an achievable goal.

Immune response to glutamic acid decarboxylase correlates with insulitis in non-obese diabetic mice

Knowing the autoantigen target(s) in an organ-specific autoimmune disease is essential to understanding its pathogenesis. Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease characterized by lymphocytic infiltration of the islets of Langerhans (insulitis) and destruction of insulin-secreting pancreatic beta-cells. Several beta-cell proteins have been identified as autoantigens, but their importance in the diabetogenic process is not known. The non-obese diabetic (NOD) mouse is a murine model for spontaneous IDDM. Here we determine the temporal sequence of T-cell and antibody responses in NOD mice to a panel of five murine beta-cell antigens and find that antibody and T-cell responses specific for the two isoforms of glutamic acid decarboxylase (GAD) are first detected in 4-week-old NOD mice. This GAD-specific reactivity coincides with the earliest detectable response to an islet extract, and with the onset of insulitis. Furthermore, NOD mice receiving intrathymic injections of GAD65 exhibit markedly reduced T-cell proliferative responses to GAD and to the rest of the panel, in addition to remaining free of diabetes. These results indicate that the spontaneous response to beta-cell antigens arises very early in life and that the anti-GAD immune response has a critical role in the disease process during this period.

An Abd transgene prevents diabetes in nonobese diabetic mice by inducing regulatory T cells

Susceptibility to the human autoimmune disease insulin-dependent diabetes mellitus is strongly associated with particular haplotypes of the major histocompatibility complex (MHC). Similarly, in a spontaneous animal model of this disease, the nonobese diabetic (NOD) mouse, the genes of the MHC play an important role in the development of diabetes. We have produced transgenic NOD mice that express the class II MHC molecule I-Ad in addition to the endogenous I-Ag7 molecules in order to study the role of these molecules in the disease process. Although the inflammatory lesions within the islets of Langerhans in the pancreas appear similar in transgenic and nontransgenic animals, transgenic mice develop diabetes with greatly diminished frequency compared to their nontransgenic littermates (10% of transgenic females by 30 weeks of age compared to 45% of nontransgenic females). Furthermore, adoptive transfer experiments show that T cells present in the transgenic mice are able to interfere with the diabetogenic process caused by T cells from nontransgenic mice. Thus, the mechanism by which I-Ad molecules protect mice from diabetes includes selecting in the thymus and/or inducing in the periphery T cells capable of inhibiting diabetes development.

Evidence for antigen driven selection in two monoclonal auto-antibodies derived from nonobese diabetic mice

The nonobese diabetic (NOD) mouse is a model of human type I diabetes. This diabetes is due to massive infiltration of the pancreatic beta cell of islets by autoreactive T cells (insulitis) followed by the destruction of insulin-producing cells. Circulating autoantibodies are also detected, notably against glutamic acid decarboxylase, peripherin and insulin. Two monoclonal autoantibodies directed against insulin and peripherin were obtained by fusing NOD spleen and myeloma cells. We report here the nucleotide sequence of the genes encoding for the V regions of these two antibodies. Somatic mutations were identified by comparing the light chain nucleotide sequence of one of these autoantibodies with its germline counterpart precursor established from NOD mice after PCR gene amplification. The other one displays N additions on both sides of the D region. These results strongly suggest that both autoantibodies have undergone diversification, either N additions or somatic mutations, and therefore present structural features of antibodies derived from animals immunized against exogenous antigens.

Following a diabetogenic T cell from genesis through pathogenesis

Nonobese diabetic (NOD) mice spontaneously develop a disease very similar to type 1 diabetes in humans. We have generated a transgenic mouse strain carrying the rearranged T cell receptor genes from a diabetogenic T cell clone derived from a NOD mouse. Self-reactive T cells expressing the transgene-encoded specificity are not tolerized in these animals, resulting in rampant insulitis and eventually diabetes. Features of the disease process emphasize two so-called check-points, recognized previously in the NOD and human diseases but easily misinterpreted. Although NOD mice are protected from insulitis and diabetes by expression of the E molecule encoded in the major histocompatibility complex, the transgenics are not, permitting us to exclude some possible mechanisms of protection.

Cellular basis of T-cell autoreactivity in autoimmune diseases

There is no doubt that T cells play a key role in the pathogenesis of autoimmune diseases (AD) both as effector and regulatory cells. Despite spectacular progress in the understanding of natural tolerance to self, owing particularly to transgenic technology, important questions remain open regarding the pathogenesis of AD, the conditions favoring the transition from benign or 'physiological' autoimmunity to deleterious autoimmunity, and the precise effector mechanisms. This review on the cellular basis of T-cell-mediated AD begins with an enumeration of the main arguments in favor of direct T-cell involvement, special emphasis being given to two animal models which have been most extensively investigated: experimental allergic encephalomyelitis, and the nonobese diabetic mouse. The question as to whether pathogenic T cells use a restricted repertoire of V beta genes is examined in the context of these two models. From here we proceed to an evaluation of the mechanisms of onset of AD, discussing both extrinsic and intrinsic factors responsible for the breakdown in T-cell tolerance and reviewing the arguments in favor of suppressor T cells being actively involved in the prevention of autoimmunity. The last two sections are devoted to the effector mechanisms responsible for tissue injury in organ-specific AD and to T-cell-directed therapeutic interventions, respectively. We discuss the two main pathogenic hypotheses based on direct intervention of cytotoxic T cells or indirect involvement of inflammatory cytokines and macrophages, and evaluate the importance of ecotaxis in leading autoreactive T cells to the site of injury. We conclude on a brief and nonexhaustive list of strategies aimed at selectively neutralizing potentially harmful T cells.

Diabetes intervention therapy

The involvement of autoreactive T cells in autoimmune diseases suggests the potential for intervention therapy in the setting of insulin-dependent diabetes mellitus. In the nonobese diabetic mouse, diabetes and insulitis have been inhibited by the modification of an amino acid in the major histocompatibility complex and by administration of anti-I-A antibody. T-cell vaccination has been shown to prevent autoimmune disease in animal models, and research is ongoing to develop monoclonal antibodies to a variety of T-cell receptor components. Strategies assessed in the clinical context include the administration of azathioprine, cyclosporine, and the antioxidant nicotinamide. Other potential strategies include the induction of specific oral tolerance, insulin prophylaxis, immunoenhancement therapy, and dietary manipulation.

In vivo administration to rhesus monkeys of a CD4-specific monoclonal antibody capable of blocking AIDS virus replication

Monoclonal antibodies (mAbs) specific for CD4 are potent inhibitors of HIV replication in vitro. These agents may be useful prophylactically or in chronic HIV infection if they can be administered without inducing immunosuppression. In the present study, we explored the safety of a CD4-specific murine mAb in rhesus monkeys. The mAb 5A8, which binds to domain 2 of the CD4 molecule, inhibits AIDS virus replication noncompetitively at a postvirus binding step. This antibody, which had a similar affinity for rhesus monkey and human CD4 cells, efficiently inhibited in vitro replication of both HIV-1 and the simian immunodeficiency virus of macaques. A single 3-mg/kg injection of mAb 5A8 into normal rhesus monkeys coated all circulating and lymph node CD4 cells for 4-6 days. CD4 cells were not cleared from circulation nor was the CD4 molecule modulated from the lymphocyte surface. In fact, administration of mAb 5A8 resulted in an approximately one-to twofold increase in absolute number of circulating CD4 cells. Repeated administration in normal rhesus monkeys resulted in CD4 lymphocyte coating with mAbs for > 9 days without CD4 cell clearance or modulation. While coated with mAbs, PBLs of these monkeys retained normal in vitro proliferative responses to mitogens and these animals generated normal humoral responses in vivo to tetanus toxoid. Loss of cell coating with mAbs in normal monkeys corresponded to the appearance of anti-mouse immunoglobulin antibodies. Thus, administration of certain anti-CD4 mAbs capable of blocking HIV replication can achieve coating of the entire CD4 cell pool in rhesus monkeys without inducing significant cell loss or immunosuppression.

Short-term administration of anti-L3T4 MoAb prevents diabetes in NOD mice

We treated 2-week-old and 8-week-old non-obese diabetic (NOD) mice with 1 mg of anti-L3T4 MoAb weekly for 4 weeks. This short-term treatment of anti-L3T4 MoAb prevented the development of overt diabetes in NOD mice, in both groups, even after cessation of the therapy. However, there were overt mononuclear cell infiltrations in the majority of islets, and no appreciable differences in the degree of insulitis between treated and control mice. There were also no significant differences in the percentage of L3T4+ T cells expressing V beta 5, V beta 8 and V beta 11 antigens between the treated and the control group. In contrast, most of the male NOD mice injected with 200 mg/kg of cyclophosphamide did not become diabetic when the spleen cells from the MoAb-treated female NOD mice were transferred to these animals 48 h before the cyclophosphamide injection. Thus, the tolerance induced by the short-term administration of anti-L3T4 MoAb to NOD mice may not be due to clonal deletion, but rather to newly generated suppressor cells in the animals.

Insulin-dependent diabetes in the NOD mouse model. I. Detection and characterization of autoantibody bound to the surface of pancreatic beta cells prior to development of the insulitis lesion in prediabetic NOD mice

Type I, insulin-dependent diabetes (IDD) results from an autoimmune response against the insulin producing pancreatic beta cells. This autoimmune reaction involves both humoral and cell-mediated factors; nevertheless, the relative role of each remains unresolved. Furthermore, while adoptive transfer experiments have provided evidence for the role of T cells in beta cell destruction, the specific events which initiate leukocyte migration into the islets (insulitis) are unknown. Earlier studies indicated that NOD pancreatic beta cells may bind small amounts of autoantibody. Because of the possible importance of an early humoral response to the initiation of insulitis and subsequent disease, we have investigated a number of aspects of this phenomenon to determine the nature and specificity of the early autoantibodies as well as the time at which autoantibody binds to beta cells. Results of this study demonstrate that NOD/Uf mice are sensitized to islet-cell associated antigens, including GAD, prior to the first appearance of insulitis; that a small percentage of the beta cells of NOD/Uf mice have autoantibody bound to their surface prior to insulitis; that sera collected from preinsulitis NOD/Uf mice contain autoantibodies which will bind to beta cells of both IDD-prone and IDD-resistant mice; and that the autoantibodies which bind pancreatic beta cells are predominantly IgM with lesser amounts of IgG and IgA. These findings suggest that, in the natural course of IDD, insulitis may develop in response to an initial autoantibody-mediated injury of beta cells.

Analysis of VH gene utilisation in the non-obese diabetic mouse

The immunoglobulin (Ig) heavy chain variable (VH) gene complexity and the VH gene utilisation pattern of the non-obese diabetic (NOD) mouse were investigated. We found that the NOD mouse displays a VH gene complexity which appears to be identical to that of the C57BL/6 mouse. Thus, Southern hybridisation using probes specific for 9 of the murine VH gene families revealed identical restriction fragment length polymorphism (RFLP) patterns in both mouse strains. As indicated by immunofluorescence analysis using allotype specific monoclonal antibodies the NOD mice were also found to carry the IgCH-1b allele. Collectively, these data suggest that the NOD mice carry an IgVH locus identical to that carried by C57BL/6. In contrast to the apparent identity at the level of germline VH gene repertoires, the pattern of VH gene utilisation differed considerably between these two mouse strains. Thus, in NOD mice the neonatal preference of D-proximal VH genes was found to be more pronounced than in C57BL/6 mice. Moreover, in contrast to adult C57BL/6 mice a D-proximal bias was evident also in adult NOD mice. On the basis of these findings we discuss the possibility that the distorted development of B cell repertoires in the NOD mouse could be directly or indirectly related to the T cell mediated, autoimmune process in the NOD mouse.

Cytokines play a central role in the pathogenesis of systemic lupus erythematosus

Excessive production of pathogenic autoantibodies is one of the hallmarks of systemic lupus erythematosus (SLE). The mechanisms that underlie this excessive production are still unclear. Although there is considerable evidence to suggest that both T cells and B cells play an important role in the etiology of SLE, convincing abnormalities at the T cell receptor or immunoglobulin gene loci have not been demonstrated. In this regard, because cytokines play such a pivotal role in the inflammatory response, a defect in the immunoregulation of B cells by cytokines should be considered as possible contender in disease etiology. The hypothesis that is proposed here is that multiple defects mediated by cytokines are present in individuals with lupus and that both cytokine production and the response of B cells to cytokines may be defective. These abnormalities could then be a central factor in the etiology of systemic lupus erythematosus.

Role of infiltrating T cells for impaired glucose metabolism in pancreatic islets isolated from non-obese diabetic mice

Pancreatic islets isolated from non-obese diabetic (NOD) mice, all of which have insulitis, exhibit an impaired glucose metabolism. In order to investigate the role of infiltrating lymphocytes for this altered metabolism, we injected 12- to 13-week-old female NOD mice with monoclonal antibodies directed against either the alpha beta-T cell receptor, CD4+ or CD8+ T cells. Control NOD mice were injected with normal rat IgG or with the vehicle (phosphate buffered saline) alone. Injection of the three different monoclonal antibodies markedly reduced the mononuclear cell infiltration. An intravenous glucose tolerance test showed no differences between the groups. Islet insulin release in response to glucose was similar in all groups. In contrast, islets isolated from the control NOD mice with insulitis showed a high basal (1.7 mmol/l glucose) glucose oxidation rate and a small increase in the glucose oxidation rate in response to a high glucose concentration (16.7 mmol/l glucose). The monoclonal antibodies counteracted the elevated basal glucose oxidation rate of the islets. Parallel studies of stimulated mononuclear cells suggested that the contribution of glucose oxidized by islet-infiltrating lymphocytes could only partially explain the observed alterations in NOD mouse islet metabolism. Culture of islets obtained from NOD mice in the presence of the cytokine interleukin-1 beta induced a similar pattern of glucose metabolism as seen earlier in IgG or phosphate-buffered saline treated control NOD mice. In conclusion, alterations in the glucose oxidation rates seem to be an early sign of disturbance in islets isolated from NOD mice. These early alterations in glucose metabolism can be reversed in vivo by monoclonal antibodies directed against effector lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the roles of CD4+ and CD8+ T cells in autoimmune diabetes of NOD mice using transfer to NOD athymic nude mice

The NOD mouse, which spontaneously develops insulitis and overt diabetes, is a model of autoimmune type I diabetes mellitus. For the precise analysis of the roles of CD4+ and CD8+ T cells in the pathogenesis of this mouse, these subsets must be transferred into recipients that are completely free of T cells and pathological changes. We used athymic NOD nude mice, which congenitally lack mature T cells and are free of insulitis and hyperglycemia up to the age of 60 weeks, as recipients for this purpose. To the nude recipients we transferred either one of a highly purified CD4+ or CD8+ T cell subset derived from non-diabetic female NOD mice; any in vivo increase in the contaminating T cell subsets was prevented by injecting the antibody homologous to it. Most of the T cell-reconstituted recipients were treated with cyclophosphamide to promote the onset of overt diabetes. Transfer of the CD8+ T cell subset alone did not induce insulitis or hyperglycemia. In contrast, transfer of the CD4+ T cell subset alone produced insulitis, but not hyperglycemia, in all the recipients. However, the subsequent transfer of CD8+ T cells into CD4+ T cell-reconstituted recipients induced severe insulitis and hyperglycemia in almost all the recipients. In these diabetic recipients, we observed severe damage of the pancreatic islets and the infiltration of a large number of CD8+ T cells into the remaining islets; insulin-secreting beta cells were no longer detected. These results suggest that CD4+ T cells play a predominant role in the development of insulitis and that CD8+ T cells migrate into the islets and are subsequently, with the aid of CD4+ T cells, differentiated into killer cells which act against beta cells.

A protective NOD islet-infiltrating CD8+ T cell clone, I.S. 2.15, has in vitro immunosuppressive properties

Type 1, insulin-dependent diabetes mellitus (IDDM) appears to result from a T cell-dependent destruction of insulin-producing pancreatic beta cells. In non-obese diabetic (NOD) mice and in other rodent models of human IDDM, final expression of disease may be controlled by protective, as well as, destructive T cell influences. Previously, a CD8+ T cell clone, I.S. 2.15, was isolated directly from islets of disease-resistant male NOD mice. Upon transfer to young NOD recipients, the non-cytolytic I.S. 21.5 T cell clone, confers in vivo protection from two forms of accelerated IDDM. The present study demonstrates that I.S. 2.15 T cells induce in vitro immunosuppression. The suppressive effects of I.S. 2.15 T cells are mediated through soluble factor(s) and are independent of T cell activation, cell contact, antigen specificity or the major histocompatibility complex (MHC). By polymerase chain reaction (PCR), I.S. 2.15 T cells contain mRNA species encoding for the potentially immunosuppressive cytokines, interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta). The T cell suppressive effects engendered by I.S. 2.15 T cells closely mimic those observed with TGF-beta. Moreover, I.S. 2.15-induced immunosuppression correlates with intracellular levels of TGF-beta mRNA. These results establish that immunoregulatory T cells are present within islets in IDDM-resistant NOD mice and may impact on final disease expression through the production of soluble mediator(s).

The use of a non-depleting anti-CD4 monoclonal antibody to re-establish tolerance to beta cells in NOD mice

The use of immunosuppressive drugs in the management of autoimmunity penalizes a large part of the immune system for the misdemeanors of a small minority of T cells. An ideal form of therapy would be one in which it were possible to render the immune system tolerant of the inciting antigens with minimal effects on other responses. We here show that it is possible to re-establish self tolerance in an animal model of insulin-dependent diabetes mellitus without prior deletion of CD4+ T cells using a short course of therapy with a non-lytic monoclonal antibody to the CD4 adhesion receptor on T cells. This tolerance can be achieved even when diabetogenic cells are already in the pancreas. Primary responses to antigens given after therapy has ceased are normal and secondary responses to antigens seen prior to, but not during, the period of antibody therapy can remain unaffected. This suggests that intervention with selected CD4 antibodies may have significant advantages over and above that provided not only by conventional immunosuppression but also over that provided by a depleting antibody.

Androgen treatment prevents diabetes in nonobese diabetic mice

The nonobese diabetic (NOD) mouse strain provides a model system for human autoimmune diabetes. This disease model is extensively used not only to examine the etiology and pathogenesis of diabetes, but also as a means to evaluate therapies. In NOD mice, the disease progresses from insulitis to islet destruction and clinical diabetes in a high percentage of female mice. In this study, androgen therapy, begun after the onset of insulitis, was found to prevent islet destruction and diabetes without eliminating the islet inflammation in female NOD mice. However, diabetes can be adoptively transferred into such hormone-treated recipients. The prevention of disease onset by androgen is likely due to the hormonal alteration of the development or function of the immune cells necessary for islet destruction.

Immunointervention in autoimmune diseases from cellular selectivity to autoantigen specificity

Immunosuppressive agents have proved to be remarkably successful in controlling the course of a growing number of autoimmune diseases. The usual occurrence of relapses when the treatment is stopped and the persisting risk of long term complications linked to over-immunosuppression have prompt the search for new approaches, aiming at more rapid and selective intervention and earlier onset of therapy. New chemicals and monoclonal antibodies presently represent the main clinical orientations, while at the experimental level major efforts are directed towards peptide therapy (autoantigen, T cell receptor) and tolerance induction.

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.

Autoantibodies against pancreatic beta-cells: characterization by western blot analysis in the non-obese diabetic (NOD) mouse

The NOD mouse is a relevant model for studying autoimmune diabetes. As in human insulin-dependent diabetes mellitus, the nature of the autoantigen towards which the immune system is directed remains to be clarified. It has been shown that T cells are central to the disease process. However, autoantibodies may be used as a probe to identify islet autoantigens to which self tolerance is defective. Using Western blot analysis, we characterized autoantibodies which are specific for a 58 kDa islet antigen and a 29 kDa antigen. The 58 kDa autoantigen was present in cellular extracts prepared from rat tumoral insulin-secreting cells (Rin5F) and NOD islets but not from most other non-insulin-secreting cell lines. By contrast the 29 kDa antigen was a ubiquitous antigen expressed in all cell lines tested and was not further characterized since it is very likely to be responsible for secondary immunization rather than play any role in the NOD disease process. Anti-58 kDa autoantibodies were detected in all diabetic male and female NOD animals as well as in sera from old non-diabetic NOD animals. Anti-58 kDa antibodies were not detected in sera from young NOD mice (less than 6 weeks of age) or in sera from other conventional laboratory strains of mice including autoimmune prone animals such as MRL/lpr and (NZB x NZW)F1 mice. A monoclonal antibody (72.2) specific for the 58 kDa structure was obtained, which allowed further characterization of the corresponding islet cell antigen. The expression of the 58 kDa antigen was evidenced by Western blot analysis in normal islets and in a mouse neuroblastoma cell line.

In vivo depletion of CD4 T cells increases B cell sensitivity to polyclonal activation: The role of interferon-γ

Chronic in vivo depletion of CD4+ T cells results in a marked increase in serum IgM levels. When normal mice were acutely depleted of CD4+ T cells, unfractionated spleen cell cultures showed an increased sensitivity to lipopolysaccharide (LPS)-induced IgM secretion. Sensitivity to LPS-induced proliferation was similar in both control cultures and cultures from CD4-depleted donors. When exogenous recombinant murine interferon-gamma (IFN-gamma) was added to spleen cell cultures from CD4-depleted donors, the sensitivity to LPS-induced IgM secretion was restored to the level seen in spleen cell cultures from control animals. IFN-gamma did not influence the proliferative response of purified B cells to LPS but was capable of profoundly inhibiting the LPS-induced differentiation of purified B cells. Thus the effect of IFN-gamma was anti-differentiative and was exerted directly on the B cell. Finally, the LPS-induced differentiation of normal spleen cells was enhanced in the presence of mAb directed against IFN-gamma. These findings illustrate that IFN-gamma plays a key role in regulating the B cell compartment response to LPS-induced differentiation. The hyper-IgM syndrome seen in association with CD4 T cell depletion may be due to a loss of in vivo production of IFN-gamma.

Quantitative and functional analyses of spleen and in situ islet immune cells before and after diabetes onset in the NOD mouse

Cytofluorometric analysis using specific monoclonal antibodies directed against the T cell antigens Thy-1.2, CD4, CD8, CD4V beta(8.1 + 8.2 + 8.3), and the antigen Mac-1 expressed by mature macrophages and NK cells were used to characterize and quantify the phenotypes of (1) unfractionated and Percoll gradient fractionated in situ islet immune cells isolated from prediabetic and diabetic female NOD mouse spleens. We found in prediabetic female mice that the majority (approximately 70%) of the in situ islet immune cells were Thy-1.2 positive T cells. CD4 positive T cells (approximately 40%) were the most abundant phenotype together with double negative T cells (approximately 20%). The percentage of CD8 positive T cells were approximately 10%, and only approximately 4% of the immune cells were Mac-1 positive. The percentages of CD4V beta (8.1 + 8.2 + 8.3) positive and double negative T cells in diabetic spleens were significantly higher in comparison to prediabetic spleens. In C57B1/6J control nondiabetic mice the percentage of double negative T cells in the spleens was significantly 4-fold lower when compared to diabetic NOD spleens. The specific cytolytic activity mediated by in situ islet immune cells against 51Cr-labeled dispersed syngeneic single-cell islet cells at an effector to target ratio of 20 was twenty- to thirty-fold higher than that mediated by prediabetic splenic lymphoid cells. It is concluded that prediabetic NOD mouse in situ islet immune cells are mostly CD4 positive and double negative T cells, and that CD4 and CD8 positive T cells in the intra-islet infiltrate warrants further evaluation as potential effector T cells in target beta-cell destruction.

Enhanced tumor necrosis factor in anti-CD3 antibody stimulated diabetic NOD mice: modulation by PGE1 and dietary lipid

Administration of OKT3 anti-CD3 monoclonal antibody (mAb) to patients for transplant rejection, is associated with a distinct and often severe clinical syndrome related to massive cytokine release. Previous reports have similarly demonstrated increased levels of serum tumor necrosis factor alpha (TNF alpha) in normal mice following administration of 1452-C11 anti-CD3 mAb. In this study, we compared serum TNF alpha levels at baseline and after anti-CD3 stimulation among three groups of mice: normal BALB/c controls, pre-diabetic non-obese diabetic (NOD) mice, and diabetic NOD mice. Baseline serum TNF alpha levels, as measured by L929 cell bioassay, were 2xhigher in diabetic NOD and 3xhigher in pre-diabetic NOD compared with BALB/c. Ninety minutes after anti-CD3 mAb stimulation, serum from BALB/c controls and pre-diabetic NOD contained 2- to 8-fold higher levels of TNF-alpha as compared to untreated control mice. In contrast, following anti-CD3 mAb, there was a dramatic 20-fold increase in serum TNF alpha in diabetic NOD mice (levels > 5000 pg/ml). Additionally, anti-CD3 mAb increased the steady-state TNF alpha mRNA transcripts. Spleens from diabetic mice given anti-CD3 mAb had higher steady-state TNF alpha mRNA than spleen from normal mice similarly treated. The enhanced release of circulating TNF alpha after anti-CD3 mAb in diabetic NOD mice was abrogated by pre-treatment of mice with prostaglandin E1 (PGE1) 30 min prior to anti-CD3 mAb stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Peripherin: an islet antigen that is cross-reactive with nonobese diabetic mouse class II gene products

The nonobese diabetic (NOD) mouse, in which major histocompatibility complex genes may be involved in the susceptibility to diabetes, has been developed as a model of autoimmune diabetes. The NOD mouse expresses I-A-encoded class II major histocompatibility complex antigens, which differ from those of other mouse haplotypes by the presence of a serine at position 57 of the A beta chain. Identifying islet autoantigens may help elucidate the role of class II antigens in the activation of autoreactive T cells and, thus, in the development of diabetes. We have detected autoantibodies directed against a 58-kDa islet cell antigen in NOD mice but not in other strains, including lupus-prone mice. Apart from insulin-secreting cells, the 58-kDa antigen was only found to be expressed by neuroblastoma cells and was identified as peripherin, an intermediate filament protein previously characterized in well-defined neuronal populations. This autoantigen cross-reacted with I-Anod class II antigens, suggesting that it may contribute to defective self-tolerance of islet beta cells in the NOD mouse.

Insulin-dependent diabetes mellitus

Type I diabetes occurs as a result of T-cell-mediated beta-cell destruction. Several candidate antigens have been described recently, including glutamic acid decarboxylase, heat shock protein 65 and peripherin. Restricted T-cell receptor V beta gene usage in non-obese diabetic mice has been suggested but not yet proven. In addition to major histocompatibility genes, several non-H-2 predisposing genes have been mapped on chromosomes 1, 3 and 11.

Suppression of diabetes in nonobese diabetic mice by oral administration of porcine insulin

Nonobese diabetic (NOD) mice spontaneously develop an autoimmune form of diabetes associated with insulitis. A number of immunomodulatory therapies have been investigated as a treatment for the disease process. Oral administration of the autoantigens myelin basic protein and collagen type II suppresses experimental models of encephalomyelitis and arthritis. We have now found that oral administration of insulin delays the onset and reduces the incidence of diabetes in NOD mice over a 1-year period in animals administered 1 mg of porcine insulin orally twice a week for 5 weeks and then weekly until 1 year of age. As expected, orally administered insulin had no metabolic effect on blood glucose levels. The severity of lymphocytic infiltration of pancreatic islets was also reduced by oral administration of insulin. Furthermore, splenic T cells from animals orally treated with insulin adoptively transfer protection against diabetes, demonstrating that oral insulin administration generates active cellular mechanisms that suppress disease. These results show that oral insulin affects diabetes and the pancreatic cellular inflammatory process in the NOD mouse and raise the possibility that oral administration of insulin or other pancreatic autoantigens may provide a new approach for the treatment of autoimmune diabetes.

Overexpression of class I major histocompatibility complex accompanies insulitis in the non-obese diabetic mouse and is prevented by anti-interferon-gamma antibody

Overexpression of class I major histocompatibility complex (MHC) proteins on pancreatic islet cells is a characteristic of autoimmune Type 1 (insulin-dependent) diabetes mellitus in humans and in animal models. Studies of post-mortem pancreases from humans with Type 1 diabetes suggest that overexpression of class I MHC proteins may precede mononuclear cell infiltration of the islets (insulitis). Pancreatic histology from the earliest stages of human Type 1 diabetes is rarely available. We have used the non-obese diabetic mouse, given cyclophosphamide to accelerate Beta-cell destruction, to investigate the temporal relationship between the overexpression of class I MHC protein and mRNA and other pathological changes associated with Beta-cell destruction. Prior to cyclophosphamide, immunoperoxidase staining showed that expression of class I MHC proteins was greater on islet cells and infiltrating inflammatory cells of the non-obese diabetic mouse than on islet cells of other mouse strains, whereas staining on exocrine cells was similar. On day three after cyclophosphamide administration, when insulitis had regressed, islet class I MHC protein expression had diminished. A dramatic increase in class I MHC protein expression occurred between days seven and nine, concomitant with reinfiltration of the islets by mononuclear cells; overexpression was seen both on islet cells and on surrounding exocrine cells, but only in the presence of mononuclear cell infiltration. By day 21, class I MHC protein overexpression was again confined to the islets, the exocrine pancreas being free of infiltration. Class I mRNA also increased dramatically by day eight but had virtually returned to normal by day 12.2+ effected by cytokines secreted by activated immuno-inflammatory cells. Class I MHC overexpression should enhance targeting of cytotoxic T cells to Beta cells bearing autoantigen.

Monoclonal, natural antibodies prevent development of diabetes in the non-obese diabetic (NOD) mouse

The development of diabetes in the non-obese diabetic (NOD) mouse is mediated by T cells of both the CD4+CD8- and CD4-CD8+ phenotypes, while B cells are not involved in the effector stage of the disease. We have recently found, however, that treatments with heterologous, polyclonal immunoglobulin (Ig) preparations, as well as suppressing the developing B cell repertoire for the first 4 weeks of life dramatically reduce the incidence of disease and the severity of insulitis, in treated mice. We have further investigated the influence of Igs on the development of autoimmunity by testing the effect of polyclonal mouse-Ig or monoclonal, natural antibodies derived from normal, neonatal BALB/c mice. We found that repeated administration of high doses of polyclonal Ig (of xenogenic or isogenic origin), given at birth, inhibits the development of insulitis, as well as diabetes. Furthermore, single injections of moderate doses of isogenic, natural monoclonal antibodies (mAb) administered at the same age, while failing to significantly alter the degree of insulitis, efficiently prevent the development of disease. The effect of mAbs was found to be related to V-region specificity, as only some mAbs of a given isotype and origin had the observed effect.

Immunoglobulin-mediated prevention of autoimmune diabetes in the non-obese diabetic (NOD) mouse

We investigated whether the development of spontaneous T-cell-mediated type I diabetes in NOD mice is influenced by B cells and immunoglobulin (Ig). During the first 4 weeks of life, B-cell development was suppressed by repeated administration of rabbit anti-mouse IgM (RaIgM), while controls received polyclonal rabbit Ig (NRIg). A reduction in the incidence of diabetes, as well as in development of insulitis, was observed after either of these treatments. However, the effect on insulitis was more pronounced in mice treated with RaIgM compared with those treated with NRIg. Furthermore, while the optimal effect of NRIg was obtained after a single injection at birth, the additional effect of RaIgM on development of insulitis was observed only after continued treatment for the first 4 weeks of life. Taken together these data suggest a possible role of Ig/B cells in the development of autoimmunity in the NOD mouse. The additional effect observed after continued suppression of the neonatal B-cell development suggests that this population may contribute significantly to the establishment of an auto-aggressive lymphocyte repertoire in the NOD mouse.

Hemolytic anemia in non-obese diabetic mice

The non-obese diabetic mouse (NOD mouse) is widely used as a model of organ-specific autoimmunity because it develops specific autoimmune destruction of pancreatic beta cells mediated by T cells and culminating in insulin-dependent diabetes mellitus. Here, we report that the NOD mouse also develops Coombs'-positive hemolytic anemia, a B cell-mediated autoimmune disease. Aged NOD mice were found to have splenomegaly and jaundice predominantly due to raised unconjugated serum bilirubin. Their hematocrits were markedly lowered, and there was a reciprocal increase in the reticulocyte count. Red blood cells (RBC) from anemic mice showed a normal lytic response to hypotonicity. RBC from non-anemic mice had normal half lives in non-anemic, non-diabetic NOD mice by 51Cr labeling but, dramatically shortened half lives in anemic mice. Similar results were obtained with RBC from anemic mice. Hemolysis could be transferred with serum from anemic mice resulting in reticulocytosis. The antibody-mediated nature of the anemia was confirmed with the direct Coombs' test. Anemia was found only in mice aged greater than 200 days and was more common in diabetic (4/8) than non-diabetic (1/16) mice at 300 days. However, by 550 days, 14/17 non-diabetic mice were affected.

Genetic dissection of T cell receptor V beta gene requirements for spontaneous murine diabetes

It has been demonstrated, in certain autoimmune disease models, that pathogenic T cells express antigen receptors of limited diversity. It has been suggested that the T cells responsible for the pathogenesis of type I diabetes mellitus might similarly demonstrate restricted T cell receptor (TCR) usage. Recently, attempts have been made to identify the V beta subset(s) that initiates and/or perpetuates the antiislet response in a mouse model of spontaneous autoimmune diabetes (non-obese diabetic [NOD] mice). In studies reported here, we have bred NOD mice to a mouse strain that congenitally lacks approximately one-half of the conventional TCR V beta alleles. Included in this deletion are TCR V beta gene products previously implicated as being involved in the pathogenesis of NOD disease. By studying second backcross-intercross animals, we were able to demonstrate that this deletion of TCR V beta gene segments did not prevent the development of insulitis or diabetes.

Immunological effects of high dose administration of anti-CD4 antibody in rheumatoid arthritis patients

A phase I/II trial of the anti-CD4 monoclonal antibody (mAb) was undertaken in seven rheumatoid arthritis patients in order, (1) to investigate changes in clinical symptoms and possible side effects, and (2) to study the pharmacokinetics and to determine the dose required to achieve saturation of antibody binding sites on blood leucocytes. BL4mAb is a murine IgG2a which binds to the group 2B epitope of the V1 N terminal domain of the CD4 molecule. It inhibits syncitium formation by human immunodeficiency virus-infected cells. BL4 was administered by one hour-long intravenous infusion each day, for 10 days. Doses were steadily increased from 20 mg/d to 40 mg/d in the first three patients (group I) in an attempt to reach a serum antibody residual level sufficient to saturate CD4+ circulating cells. The three other patients (group II) received a dose of 40 mg/d during 10 consecutive days. One patient who presented chills and mild fever during the first BL4 infusion was not included in the analysis. No clinical side effects were observed in the six other BL4-treated patients. Clinical parameters of disease activity were improved within the first 14 days. Clinical improvement was still significant at day 30 in five patients, but at day 60, only the Ritchie index was still below pretreatment levels. Delayed type hypersensitivity reactions decreased in the three patients who exhibited positive reactions before BL4 administration. A transient drop in peripheral blood CD4+ lymphocyte counts occurred during each infusion in the first days of treatment. Pre-infusion CD4+ lymphocyte counts were moderately decreased within the first 8 days, but rose to pretreatment levels 3 days after the last infusion. BL4 residual levels in serum steadily increased to reach 8.0 micrograms/ml in group I and 9.8 micrograms/ml in group II. Saturation of BL4 binding sites was achieved after 2 days of treatment in all patients of group II but in only one of group I. Four out of six patients produced antibodies against the anti-CD4 mAb. Immunization appeared between days 12 and 50. This study shows that saturation of anti-CD4 mAb binding sites can be achieved by infusions of high doses (40 mg/d) of BL4 without clinical side effects. The results would encourage further placebo-controlled trials, since no definite conclusion can be drawn from the present study as regards clinical efficacy.

Sialadenitis in nonobese diabetic mice: transfer into syngeneic healthy neonates by splenic T lymphocytes

In the present study, we showed that both male and female nonobese diabetic (NOD) mice simultaneously develop frequent lymphocyte infiltrations in salivary submandibular glands (sialadenitis), very similar to those reported in the salivary glands of patients with Sjögren syndrome. These lesions were observed only in mice with pancreas exhibiting insulitis. The incidence of sialadenitis increased with the severity of insulitis. At the initial stage, small focal infiltrates were predominantly located around blood vessels. In older animals, inflammatory cells surrounded blood vessels and ducts. Most of the infiltrating cells proved to be L3T4+, whereas Lyt-2+ cells were comparatively few. Autoantibodies against duct epithelial cells were shown, but the degree of tissue invasion was not related to the existence of such antibodies. Antinuclear antibodies were also observed. These salivary gland infiltrates could be transferred in vivo to NOD neonates of both sexes by splenic T lymphocytes as well as by total spleen cells. These results suggest that sialadenitis in NOD mice is T cell mediated and may be related to insulitis.