Three recessive loci required for insulin-dependent diabetes in nonobese diabetic mice

Assignment of the gene for intercellular adhesion molecule-1 (Icam-1) to proximal mouse chromosome 9

Intercellular adhesion molecule-1 (ICAM-1) is an integral membrane protein, a member of the immunoglobulin superfamily, and a ligand for LFA-1, a beta 2 leukocyte integrin. ICAM-1 has a tissue distribution similar to that of the major histocompatibility complex class II antigens and is likely to play a role in inflammatory responses. We have mapped this gene to proximal mouse chromosome 9 by using mouse-hamster somatic cell hybrids and an interspecies backcross. Since human ICAM-1 maps to chromosome 19, it joins the LDL receptor to establish a new conserved syntenic segment between human chromosome 19 and proximal mouse chromosome 9. Murine Icam-1 maps between Cbl-2 and the centromere in the same region as one of the susceptibility genes for insulin-dependent diabetes mellitus (Idd-2) that is postulated to play a role in immune function and inflammation leading to insulitis. The mapping of Icam-1 to the region known to contain the Idd-2 gene raises the question of whether the phenotypic differences attributed to the Idd-2 locus might be due to genetic variation in Icam-1.

Susceptibility to type I diabetes in women is associated with the CD3 epsilon locus on chromosome 11

Type I diabetes is associated with the DQ loci of the MHC and to a lesser extent with the T cell antigen receptor (TcR) beta chain genes. The non-obese diabetic (NOD) mouse is an animal model of human diabetes, in which up to 90% of female mice develop overt insulin-dependent diabetes. Genetic studies in the NOD mouse suggest that there are at least three diabetogenic genes; one that maps to the MHC, another that may map to the mouse Thy-I locus, and a third that has still to be identified. We have investigated loci in the vicinity of the human Thy-I locus on chromosome 11q23 and report here the results of restriction fragment length polymorphism (RFLP) analysis of the CD3 epsilon locus of 168 Caucasoid patients with type I diabetes. While no association was found between this locus and type I diabetes, a significant difference in the frequency of the CD3 epsilon 8-kb allele was found between male and female patients (0.268 versus 0.430; P less than 0.0025, Pc = 0.02) and between female patients and healthy female controls (0.430 versus 0.267; P less than 0.015). These results suggest that a gene residing on chromosome 11q23 may confer susceptibility to type I diabetes in women.

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.

Transgenic models of T-cell self tolerance and autoimmunity

Self-tolerance is generally induced by intrathymic clonal deletion of T cells with reactivity directed to antigens synthesized within the thymus (Kappler et al. 1987, Kisielow et al. 1988). It may also be induced in peripheral T cells when these encounter antigens unique to extra-thymic tissues. Two transgenic models have been particularly useful in the study of peripheral self tolerance: in one model, a known antigen is expressed in a particular extra-thymic site; in the other, the T-cell repertoire is predominantly reactive to this antigen. We, and others, have shown that expression of class I or II MHC molecules in defined extra-thymic sites leads to a state of T-cell tolerance. To account for this, we have proposed two hypotheses which have different implications for autoimmune disease. According to one, tolerance is imposed by deletion or functional silencing of specific high-affinity cytolytic T cells; alternatively, the target cell for tolerance induction may be a regulatory IL-2-producing T-cell, rather than the effector cell itself. To distinguish between these hypotheses it is essential to examine the fate of T cells which have the potential to react to the transgene product. Since the frequency of such T cells is low and there is no dominant clonotype for H-2Kb, which is the class I molecule we used, it was necessary to create double transgenic mice by mating class I transgenic mice with transgenic mice whose T-cell pool was compared of cells reactive to H-2Kb and could be detected by an antibody directed to the TCR. Initial studies showed that such T cells did persist despite the presence of antigen to which they may be reactive. If these double transgenic mice can be shown to be tolerant, they will offer a rich source of tolerant T cells for detailed investigation of their phenotype and fate, and they will be most useful in enabling us to probe the mechanisms responsible for the induction of peripheral self tolerance. Transgenic mouse technology has also been used successfully to unravel the genetic influences which may lead to or prevent autoimmunity. In particular, we have prevented autoimmune diabetes in the nonobese diabetic mouse by introducing a non-NOD MHC class II gene and further work is implicating the failure of intrathymic positive selection of a protective cell as one step in the pathogenesis of diabetes in NOD mice.

Detection of DNA polymorphisms between two inbred mouse strains--limitations of restriction fragment length polymorphisms (RFLPs)

Type I (insulin-dependent) diabetes in humans is characterized by a T cell mediated destruction of insulin-secreting pancreatic beta cells. This autoimmune response is very similar to that seen in the non-obese diabetic (NOD) mouse strain. Originally bred from the ICR cataract-prone strain, NOD mice spontaneously develop T cell mediated insulitis and type I diabetes by the age of 6 months. Backcross studies with the NOD mouse strain indicate segregation of at least three recessive genes. One of these, Iddm-1, has been shown to be tightly linked to the mouse MHC, H-2 on chromosome 17. Comparative studies with diabetic patients has also shown linkage to human HLA with protective and predisposing haplotypes being present within the population. In this study we have attempted to identify restriction fragment length polymorphisms (RFLPs) between the genomes of the NOD mouse strain and the diabetes-resistant strain C57BL/10. Such polymorphic loci will be used to screen DNAs from backcross animals that are diagnosed diabetic in an attempt to identify probes linked to the non-H2 disease susceptibility genes.

Role of the first external domain of I-A beta chain in immune responses and diabetes in non-obese diabetic (NOD) mice

Diabetes in the non-obese diabetic (NOD) mouse is a multigenic autoimmune disease and is possibly controlled by three recessive loci, including one that is linked to the major histocompatibility complex (MHC). The first external domain of the Class II MHC I-A beta chain in these mice is unique and has been suggested as being responsible for autoimmunity. The I-A alpha chain in these mice is I-A alpha d, and they lack the expression of I-E molecules. We have investigated immune responses to various Ir gene control antigens in NOD mice to determine the influence of the NOD Ia and particularly the I-A beta chain. We find that sheep insulin is highly immunogenic while other insulins are weakly immunogenic in these mice. Hen egg lysozyme, pigeon cytochrome C and the synthetic polypeptide Poly 18, Poly EYK(EYA)5 antigen produce good antibody responses. Apart from H-2d, NOD are the only mice where Poly 18 antigen is immunogenic. In these mice Poly 18 induced good T-cell proliferative response, which was inhibited by anti-Ia antibody, and the mice were able to respond to tyrosine-containing polypeptide Poly EYA but not to the phenylalanine-containing antigen Poly EFA. We also found that synthetic peptide 48-60 of the NOD I-A beta chain is highly immunogenic in syngeneic NOD mice both for T cells and B cells. Using an I-A beta chain-specific monoclonal antibody, we are able to prevent induction of diabetes when the antibody was administrated in prediabetic, young mice. Our results suggest that the immune response to various antigens and autoimmune diabetes in NOD mice is directly influenced by the I-A beta chain.

MHC-linked protection from diabetes dissociated from clonal deletion of T cells

The I-E molecule of the major histocompatibility complex (MHC) can prevent the spontaneous development of diabetes in nonobese diabetic (NOD) mice. The mechanism of this protection has been investigated by breeding wild-type and promoter-mutated E kappa alpha transgenes onto the NOD genetic background. Animals carrying the various mutated transgenes expressed I-E on different subsets of immunocompetent cells, and thus cells important for the I-E protective effect could be identified. Although the wild-type transgene prevented the infiltration of lymphocytes into pancreatic islets, none of the mutants did. However, all of the transgenes could mediate the intrathymic elimination of T cells bearing antigen receptors with variable regions that recognize I-E. Thus, the I-E molecule does not protect NOD mice from diabetes simply by inducing the deletion of self-reactive T cells.

Two-disease-locus model: segregation analysis using information on two markers in nuclear families. Application to IDDM

In the present paper, an extension of segregation analysis is proposed using information on the joint segregation of two unlinked markers conditional on the disease status in nuclear families, in order to consider two-locus models with one locus linked to the first marker and the other linked to the second marker. We propose tests for examining evidence for the effect of genes located at these two loci and whether this effect is multiplicative or not. This method is then applied to a sample of IDDM families typed for the HLA and Gm markers to test, in addition to a factor of the HLA region, the potential involvement of the Gm system in the susceptibility to IDDM. The analysis does not provide evidence for such an involvement.

A detailed genetic map of the long arm of chromosome 11

We describe 14 new restriction fragment length polymorphisms, corresponding to 13 loci on the long arm of chromosome 11. A detailed genetic map of chromosome 11q has been constructed from these and other loci (a total of 31 loci) typed in 59 reference families. The 23 most informative markers were selected to establish a map with a strongly supported order; regional localizations are provided for eight other markers. The loci span 88 cM in males and 148 cM in females and form a dense continuum on 11q. These ordered polymorphic markers will be of help in studying the genes responsible for several diseases that have been localized to this region, including genes responsible for multiple endocrine neoplasia type I (MEN1), ataxia telangiectasia (AT), tuberous sclerosis (TSC), and some forms of asthma and rhinitis.

Prevention of diabetes in non-obese diabetic I-Ak transgenic mice

The non-obese diabetic (NOD) mouse develops insulin-dependent diabetes mellitus (IDDM) with mononuclear cell infiltration of the islets of Langerhans and selective destruction of the insulin-producing beta-cells, as in humans. Most infiltrating cells are T lymphocytes, and most of these carry the CD4 antigen. Adoptive transfer of T cells from diabetic NOD mice into irradiated NOD or athymic nude NOD mice induces diabetes. Susceptibility to IDDM in NOD mice is polygenic, with one gene linked to the major histocompatibility complex class II locus, which in NOD mice expresses a unique I-A molecule but no I-E. Speculation exists as to the role of the I-A molecule in the diabetes susceptibility of NOD mice, especially regarding the significance of specific unique residues. To examine the role of the NOD I-A molecule in IDDM pathogenesis, we made NOD/Lt mice transgenic for I-Ak by microinjecting I-Ak alpha- and beta-genes into fertilized NOD/Lt eggs. Insulitis was markedly reduced and diabetes prevented in NOD/Lt mice expressing I-Ak.

Autoimmune diseases: the failure of self tolerance

The ability to discriminate between self and nonself antigens is vital to the functioning of the immune system as a specific defense against invading microorganisms. Failure of the immune system to "tolerate" self tissues can result in pathological autoimmune states leading to debilitating illness and sometimes death. The induction of autoimmunity involves genetic and environmental factors that have focused the attention of researchers on the trimolecular complex formed by major histocompatibility complex molecules, antigen, and T cell receptors. Detailed molecular characterization of these components points to potential strategies for disease intervention.

Reversal of beta-cell suppression in vitro in pancreatic islets isolated from nonobese diabetic mice during the phase preceding insulin-dependent diabetes mellitus

Insulin-dependent diabetes mellitus (IDDM) is characterized by a progressive autoimmune destruction of the pancreatic beta-cells. One of the best-suited animal models for IDDM is the nonobese diabetic (NOD) mouse. In this investigation pancreatic islets were isolated from female NOD mice aged 5-7, 8-11, and 12-13 wk and examined immediately (day 0) or after 7 d of culture (day 7). The mice showed a progressive disturbance in glucose tolerance with age, and a correspondingly increased frequency of pancreatic insulitis. Islets isolated from the oldest mice often contained inflammatory cells on day 0, which resulted in an elevated islet DNA content. During culture these islets became depleted of infiltrating cells and the DNA content of the islets decreased on day 7. Islets of the eldest mice failed to respond with insulin secretion to high glucose, whereas a response was observed in the other groups. After culture all groups of islets showed a markedly improved insulin secretion. Islets from the 12-13-wk-old mice displayed a lower glucose oxidation rate at 16.7 mM glucose on day 0 compared with day 7. Islet (pro)insulin and total protein biosynthesis was essentially unaffected. In conclusion, islets obtained from 12-13-wk-old NOD mice exhibit an impaired glucose metabolism, which may explain the suppressed insulin secretion observed immediately after isolation. This inhibition of beta-cell function can be reversed in vitro. Thus, there may be a stage during development of IDDM when beta-cell destruction can be counteracted and beta-cell function restored, provided the immune aggression is arrested.

Restriction fragment length polymorphisms in the major histocompatibility complex of the non-obese diabetic mouse

The inbred non-obese diabetic (NOD) mouse is a spontaneous model for insulin-dependent diabetes mellitus (IDDM). As in man and BB rats, IDDM in the NOD mouse has an autoimmune aetiology. The disease is controlled by several genes, one of which, Idd-1, has been mapped to the major histocompatibility complex (MHC) on chromosome 17. However, Idd-1 has not yet been identified. To facilitate the identification of Idd-1 we have further analysed the MHC region for restriction fragment length polymorphisms and we find that the NOD mouse has a distinct haplotype: H-2K1nod Kd A beta nod A alpha d E beta nod TNF-alpha beta. In addition, the NOD mouse shows some similarities with the H-2b haplotype in the Q region, in that either the Q7 or the Q9 gene seems to be like that in the b-haplotype and that the Qa2 antigen is expressed, while other parts of this region are distinct from the b- as well as the d- haplotype. In contrast, the sister strain, the non-obese normal (NON) mouse, derived from the same cataract-prone line of mice as the NOD mouse, has an MHC Class I region indistinguishable from the b-haplotype, but the MHC Class II region is distinct from the NOD mouse as well as the b-, d- and k-haplotype.

Immune deficiency of the CTS mouse. I. Deficiency of in vitro T cell-mediated immune response

The cataract Shionogi (CTS) mouse characterized by cataracts and microphthalmia is a sister strain of the NOD mouse. We have made the immunological characterization of the CTS mouse by means of in vitro assays. Splenocytes of the CTS mouse were very low in the responsiveness to T cell mitogens such as Con A and PHA but not to a B cell mitogen, LPS. The production of IL 2 and expression of IL 2-receptor of spleen cells after in vitro stimulation with Con A decreased in the CTS mouse, when compared with those in the NOD and the other reference strains. In mixed lymphocyte culture, CTS splenocytes did not proliferate and did not generate cytotoxic T lymphocytes when cocultured with splenocytes of the C3H/He mouse. The NK activity against YAC-1 target cells was lower in the CTS mouse than in the C3H/He mouse, an NK high responder, but higher than in the NOD mouse, a low responder. These results suggest that the CTS mouse is deficient in T cells. Subset analysis of splenic lymphocytes of the CTS mouse using flow cytometry revealed that the percentage of T cells in the CTS mouse was significantly lower than those in the reference strains, which was consistent with the reduced responsiveness to T cell mitogens in the CTS mouse. The deficiency in the Ly-2+ T cell subset was particularly striking. However, the response to PHA of the splenocytes of the CTS mouse was normalized when T cells were enriched by nylon wool-passing and cell-sorting. Therefore, it seems that decreased T cell activity is due to a decrease in T cell number and not to dysfunction of individual T cells.

The expression of influenza virus hemagglutinin in the pancreatic beta cells of transgenic mice results in autoimmune diabetes

Insulin-dependent diabetes mellitus results from the autoimmune destruction of the insulin-producing beta cells of the pancreatic islets. The target antigen(s) involved in this immunopathological process has not been identified. Our strategy was to determine whether expression of a novel surface antigen by murine pancreatic beta cells would result in insulin-dependent diabetes mellitus. We have generated lines of transgenic mice (RIP-HA) that express the hemagglutinin of the A/Japan/305/57 strain of influenza virus on their insulin-producing beta cells. Hyperglycemia developed in mice derived from all three founders at a frequency varying from 13% to 27%, and was associated with lymphocytic infiltration of the islets and a humoral response against beta cell antigens, including hemagglutinin. These results suggest that the RIP-HA mice should provide a useful system in which to study the cellular interactions involved in the induction of self-tolerance and autoimmunity.

A single recessive non-MHC diabetogenic gene determines the development of insulitis in the presence of an MHC-linked diabetogenic gene in NOD mice

To study the genetic control of insulitis in non-obese diabetic (NOD) mice, we performed breeding studies in crosses of NOD with non-diabetic strains, ICR-L-line Ishibe (ILI), non-obese non-diabetic (NON) and C3H/He mice. The ILI mouse serologically shared the same MHC Class I and Class II as the NOD mouse. Insulitis was defined as islets invaded by lymphoid cells. Periductular, perivascular and peri-insular lymphoid cell infiltrations were often observed in NOD mice and appear to be the initial lesion leading to insulitis. Such lesions, however, were found in 1-year-old ICR, ILI, NON and Cataract Shionogi (CTS) mice of the NOD's sister strain. The lymphoid cells did not invade the islets in ICR, ILI, NON and CTS mice. The incidence of insulitis was 0% in F1 generations and 40% in female backcrosses (BC) [(ILI x NOD)F1 x NOD] at 9 weeks of age, 48 and 50% in BC[(NON x NOD)F1 x NOD] and BC[(C3H/He x NOD)F1 x NOD] at 1 year of age, respectively. Backcross animals were typed for the MHC to investigate correlation between the development of insulitis and MHC haplotypes. Among the backcross females with insulitis, approximately half the animals were heterozygous for MHC(non/nod) in BC[(NON x NOD)F1 x NOD] and MHC(k/nod) in BC[(C3H x NOD)F1 x NOD]. Among the backcross females with no insulitis, approximately half the animals were homozygous for MHC(nod/nod) in BC[(NON x NOD)F1 x NOD] and in BC[(C3H x NOD)F1 x NOD]. The results suggest that a single recessive non-MHC diabetogenic gene determines the development of insulitis regardless of NOD MHC homozygosity or heterozygosity.

Transplantation analysis of B cell destruction in (NOD x CBA)F1 mouse bone marrow chimeras

F1 hybrids produced by outcross of non-obese diabetic (NOD) mice with diabetes resistant strains are also diabetes resistant. This resistance is abrogated if F1 hybrids are lethally irradiated and then haematopoietically reconstituted with NOD bone marrow. This model was employed to determine whether T lymphocyte recognition and elimination of pancreatic B cells in NOD mice is restricted by the MHC haplotype of the target B cell. Diabetes resistant (NOD/Lt x CBA/J)F1 hybrids were lethally irradiated and reconstituted with NOD/Lt bone marrow. Following haematopoietic reconstitution, donor matched NOD/Lt or CBA/J pancreatic islet and anterior pituitary grafts were grafted under a renal capsule to determine whether effector cells derived from NOD/Lt marrow progenitors would reject islet grafts in a MHC restricted fashion. The H-2k haplotype expressed by CBA/J mice differs from all known loci of the unique H-2 haplotype of NOD; therefore, if NOD/Lt T lymphocytes eliminate pancreatic B cells in a MHC restricted fashion. NOD islet grafts would be eliminated in these chimeras while CBA islet grafts would be retained. Overt diabetes developed in 80% of the female and 40% of the male F1 hybrids following reconstitution with NOD/Lt marrow, while no hybrids reconstituted with CBA/J marrow became diabetic through a year of age. The retention of CBA/J skin and pituitary grafts in NOD/Lt marrow reconstituted F1 hybrids confirmed that the F1 thymic environment imparted tolerance to CBA/J alloantigens. Nonetheless, responses to a T cell dependent model antigen were restricted to the unique MHC haplotype of NOD. This was associated in the hyperglycaemic chimeras with rejection (8-21 days post-implantation) of both CBA/J and NOD/Lt islet grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

The genetics of insulin-dependent diabetes in the BB rat

Very little is known about the genes involved in the pathogenesis of IDDM. One component is known to be linked to the major histocompatibility complex, but the other components are unknown. We know from the major animals models of IDDM, both the NOD mouse and the BB rat, that the disease is under multigenic control. However, due to the size and complexity of the mammalian genome as well as to the lack of useful clues, the location and identity of the other genes remains a mystery. This is compounded by the fact that well-characterized genetic markers are not available for all regions of the mammalian genome, and it is likely that at least some of the genes of interest are located in these regions. The testing of pedigrees for the linkage of RFLP with the genetic factors involved in IDDM promises to be the most effective means of mapping, and ultimately identifying, these genes. However, the number of genes which are theoretically necessary to test for linkage makes even this approach impractical. Here, we have described here how the amount of work and time can be significantly reduced by utilizing repetitive DNA sequences as probes for the linkage of random RFLPs to diabetes. With each screening, one can simultaneously test multiple unlinked loci in the genome. Preliminary results which show promising linkage to two of the genetic components have been presented, thereby supporting the usefulness of this approach.

Major histocompatibility complex-linked diabetogenic gene of the nonobese diabetic mouse. Analysis of genomic DNA amplified by the polymerase chain reaction

Inheritance of insulin-dependent diabetes mellitus (IDDM) is polygenic, and at least one of the genes conferring susceptibility to diabetes is tightly linked to the MHC. Recent studies have suggested that DQB1 of humans and I-A beta of mice are closely associated with susceptibility and resistance to IDDM. For further characterization and localization of the MHC-linked diabetogenic gene, we studied the genomic sequence of the A beta gene of the nonobese diabetic (NOD) mouse, an animal model of IDDM, in comparison with those of its sister strains, nonobese nondiabetic and cataract Shionogi (CTS) mice, and the original strain, outbred Imperial Cancer Research (ICR) mice. Genomic DNAs from these strains were amplified in vitro by the polymerase chain reaction with thermostable Taq polymerase. The amplified sequences were analyzed by restriction endonuclease digestion, hybridization with allele-specific oligonucleotide probes, and direct sequencing. The unique I-A beta sequence of NOD mice was observed in the sister strain, CTS mice, and in one mouse of the original strain, outbred ICR mice. These data together with the results of MAb typing of MHC molecules and restriction mapping of the I-A region suggest that the unique class II MHC of NOD mice is not the result of a recent mutation, but is derived from the original strain. Since class I MHC of CTS mice is different from the MHC of NOD mice at both the K and D loci, CTS mice are a naturally occurring recombinant strain with NOD type class II MHC and non-NOD type class I MHC. Thus, breeding studies in crosses of NOD with CTS mice should provide biological information on whether the unique class II MHC of NOD mice is diabetogenic.

Genetic linkage and complex diseases, with special reference to psychiatric disorders

Recent linkage findings for psychiatric disorders, in particular schizophrenia, manic-depression, and Alzheimer disease, have raised a number of important conceptual issues regarding the genetic etiology of these diseases, as well as the appropriate interpretation of linkage results in studying complex diseases. Perspectives on mode of inheritance, genetic heterogeneity, and phenotypic variation are given.

Immunostimulation circumvents diabetes in NOD/Lt mice

Diabetes susceptibility in non-obese diabetic (NOD) mice may entail faulty activation of immunoregulatory cells resulting from cytokine deficiencies. Depletion of T cells prevents disease onset in these mice. Since we had previously shown that IL-2 treatment in vivo restored the ability of NOD/Lt mice to produce self-restricted suppressor T cells (Ts) in a syngeneic mixed lymphocyte reaction (SMLR), we investigated the possibility that diabetes could be circumvented by treatment with immunostimulatory agents that increase cytokine production. By 20 weeks of age, 75% of vehicle-treated NOD/Lt female controls had become glycosuric, while glycosuria developed in only 17% of NOD/Lt females injected with human recombinant interleukin-2 (rIL-2, 250 U twice weekly) beginning at 6 weeks of age. Treatment of mice with Poly [I:C] alone [50 micrograms twice weekly, an inducer of Interferon (IFN) alpha/beta] or in conjunction with rIL-2 was even more effective, completely preventing glycosuria for 20 weeks. However, therapeutic effects required continuous administration of the immunostimulants since pancreatic insulin content declined and severity of insulitis increased following cessation of treatment. IL-2 treatment increased transcription of interleukin-1 (IL-1) mRNA in peritoneal macrophages and increased lipopolysaccharide (LPS)-stimulated IL-1 secretion in comparison to controls. In the presence of stimulators from IL-2-treated mice, T lymphocytes isolated from both controls and IL-2-treated NOD/Lt mice proliferated in a SMLR and acquired Ts function. Peritoneal macrophages from Poly [I:C]-treated mice exhibited increased IFN alpha gene transcription and LPS-stimulated IL-1 secretion. T cells isolated from Poly [I:C]-treated mice were capable of suppressing NOD-Lt T cell responses to alloantigens in a mixed lymphocyte culture without prior activation in a SMLR. Thus, Poly [I:C] treatment may recruit a different population of regulatory cells than those elicited by treatment with IL-2. However, the mechanisms by which autoreactive T-cell clones may be regulated by these two treatments in NOD/Lt mice may be synergistic. These results indicate that in addition to T-cell depletion protocols, diabetes in NOD mice can be prevented by treatment with immunostimulatory agents.

Allelic T-cell receptor alpha complexes have little or no influence on susceptibility to type 1 diabetes

We performed a multiple-affected-sib study to determine if T-cell receptor alpha-chain alleles affect susceptibility to insulin-dependent diabetes mellitus. Restriction fragment length polymorphisms were used to follow the segregation of allelic T-cell receptor alpha complexes within the families. The segregation of T-cell receptor alpha alleles in 29 multiplex families revealed no significant tendency for affected sibs to share T-cell receptor alpha-chain alleles more often than would be expected by chance alone (p greater than 0.2). In contrast, the same type of analysis for HLA alleles easily detected the well-known linkage of insulin-dependent diabetes mellitus susceptibility to the HLA complex (p = 0.003). We suggest that the importance of HLA alleles in insulin-dependent diabetes mellitus susceptibility and the lack of importance of T-cell receptor alpha alleles result from the different strategies by which HLA and T-cell receptor molecules achieve antigen-binding diversity: multiple loci and allelic diversity in the case of HLA; combinatorial, junctional, and N-region diversity in the case of the T-cell receptor. In this paper we also describe three new restriction fragment length polymorphisms of the T-cell receptor alpha complex and a new method for testing the significance of linkage in multiple-affected-sib studies.

MHC antigen induction by interferon gamma on cultured mouse pancreatic beta cells and macrophages. Genetic analysis of strain differences and discovery of an "occult" class I-like antigen in NOD/Lt mice

This study provides a basis for understanding the wide variations reported in the literature in IFN-gamma inducibility of class II MHC antigens on murine beta cells. Inducibility is not an intrinsic property of all mouse beta cells, but instead depends upon strain- (and tissue-) specific response modifying factors. This was demonstrated by comparison of constitutive and IFN-gamma-induced class I and class II MHC gene products on cultured islet cell monolayers. Islet cultures were established from autoimmune diabetes-prone NOD/Lt mice, diabetes-resistant NON/Lt and CBA/J mice, as well as F1 hybrids between these latter two strains and NOD/Lt. Cultures of peritoneal macrophages (M phi) from each strain were established as controls. After 3 wk of culture (with incubation in the presence or absence of IFN-gamma during the last 6 d), constitutive expression as well as IFN-gamma induction of class I MHC antigen expression was demonstrated on NOD/Lt and NON/Lt islet cells by antibody plus complement-mediated cytotoxicity. Although CBA/J islets and M phi did not maintain constitutive class I or class II antigen expression in culture in the absence of IFN-gamma, class I H-2Kk antigen was IFN-gamma inducible. Whereas IFN-gamma-induced class II I-Ak antigen on CBA/J M phi, it failed to induce this antigen on CBA/J islets. In contrast, I-A antigens were IFN-gamma inducible on NOD/Lt and NON/Lt islets and M phi. In (CBA x NOD)F1 hybrids, loss of IFN-gamma inducibility of the I-ANOD product established that suppression was mediated by a trans-acting factor from the CBA/J genome. In the course of these studies, IFN-gamma inducibility of a crossreactive occult class I-like antigen on both NOD/Lt islet cell and M phi cultures was unexpectedly detected when mAb 28-13-3 (public specificity 39, reactive with H-2Kb,f) was used as a negative control. Although not detectable by cytofluorographic analysis of freshly isolated NOD/Lt splenic leukocytes, occult antigen could be induced on NOD/Lt peritoneal macrophages (M phi) cultured for 3 d in IFN-gamma. Time course of induction showed the occult antigen to be distinct from NOD/Lt class I and II gene products. In both islet cell and M phi cultures established from (CBA x NOD)F1 hybrids, trans-suppressive factor(s) from the CBA/J genome not only suppressed IFN-gamma-induced expression of I-ANOD, but additionally suppressed occult antigen induction. Backcross of F1 to both parental strains indicated that the occult locus was on Chr 17, tightly linked to MHC.(ABSTRACT TRUNCATED AT 400 WORDS)

Lessons from the NOD mouse for the pathogenesis and immunotherapy of human type 1 (insulin-dependent) diabetes mellitus

Suitable animal models of human Type 1 (insulin-dependent) diabetes mellitus have long been sought, in particular a model that would permit detailed histological and immunological investigation of changes in the islet preceding the metabolic disorder. This would allow hypotheses as to pathogenesis of the condition to be examined and interventions such as immunotherapy to be tested. The most widely studied models include the low-dose streptozotocin induced diabetic mouse and the BB rat, but both differ in important respects from the human disease. In this review we describe one highly successful model, the non obese diabetic mouse. Selected aspects of pathogenesis and immunotherapy are presented and analogies with human Type 1 diabetes discussed.

Recombinant human tumor necrosis factor alpha suppresses autoimmune diabetes in nonobese diabetic mice

We previously reported that administration of a streptococcal preparation (OK-432) inhibited insulitis and development of autoimmune diabetes in nonobese diabetic (NOD) mice and BB rats as animals models of insulin-dependent diabetes mellitus. In this study, we screened various cytokines that could be induced by OK-432 in vivo, for their preventive effect against diabetes in NOD mice. Among recombinant mouse IFN gamma, human IL1 alpha, human IL2, mouse granulocyte-macrophage colony-stimulating factor and human TNF alpha, only human TNF alpha suppressed insulitis and significantly (P less than 0.001) inhibited development of diabetes. NOD mice were the lowest producers of the mRNA of TNF and serum TNF on stimulation with OK-432 or with IFN gamma plus LPS, compared with C57BL/6, C3H/He, and Balb/c mice. The results imply a role for low productivity of TNF in the pathogenesis of autoimmune diabetes in NOD mice.

Physical mapping of complex genomes by cosmid multiplex analysis

A rapid and powerful approach for linking individual clones of a cosmid library and the assembly of a large physical map is presented, which depends on the simultaneous analysis of many cosmid clones for overlapping regions. This method uses cosmid vectors that contain endogenous bacteriophage T3 and T7 promoters to allow for the identification of overlapping clones through the synthesis of end-specific RNA probes. A genomic library is constructed and organized as an ordered matrix such that each clone is assigned an identifying coordinate. DNA from mixtures of cosmid clones is pooled such that each pool contains only one common member with any other pool, RNA probes are prepared from mixtures of cosmid clones, and groups of clones overlapping with the constituents of the mixtures are determined by hybridization. Pooled probes are most simply prepared by grouping clones according to the rows and columns of the library matrix. The pairwise comparison of data generated by the hybridization of mixed probes can be decoded by using simple algorithms that predict the order and linkage of all clones in the collection and organize them into predicted contigs. To demonstrate the feasibility of multiplexed analysis of cosmids, a genomic library was prepared from a mouse-human somatic cell hybrid that contains a portion of the long arm of human chromosome 11. Preparation, arrangement on a matrix, and analysis of pooled cosmid clones from this collection resulted in the detection of 1099 linked pairs of cosmids, which could be assembled into 315 contigs. Thus, with a minimal amount of effort, a substantial portion of this genomic region has been linked in multiple overlapping contigs. This method may have practical applications in the large-scale mapping and sequencing of mammalian genomes.

The role of class II major histocompatibility complex antigens in autoimmune diabetes: animal models

Like human insulin-dependent diabetes, autoimmune diabetes in BB rats and NOD mice is under control of Class II genes of the major histocompatibility complex. The mechanisms of expression of these genes is still unclear. No aberrant expression of Class II antigens was found in BB rats at the onset of diabetes. The putative role of inadequate Class II-linked suppressor control is suggested, however, by the observation that in vivo treatment with anti-Class II monoclonal antibody prevents the onset of diabetes in NOD mice, and that this protection can be transfer by CD4+ T cells.

The natural history of lymphocyte subsets infiltrating the pancreas of NOD mice

A longitudinal study of lymphocytic infiltration in the endocrine pancreas of non-obese diabetic mice was performed to investigate the role of different lymphocyte subsets in the pathogenesis of diabetes. The incidence of insulitis and the percentage of mononuclear cell subsets in the pancreas were evaluated in non-obese diabetic mice of various ages (5, 9, 13, 17, 22, 29 and 36 weeks). Cryostat sections of pancreas were stained with heamatoxilin-eosin or with different monoclonal antibodies against total T lymphocytes, helper T lymphocytes, cytotoxic/suppressor T lymphocytes, activated interleukin 2 receptor positive lymphocytes and B lymphocytes. A monoclonal antibody against Class-II antigens was also used. Positive cells were revealed by the immunoperoxidase technique. Insulitis was found in 5 weeks old mice but to a lesser extent than in adult animals. No significant variation between infiltrating cell subsets was found in different age groups. T lymphocytes ranged between 20.4% and 28.1%, B lymphocytes between 28.8% and 30.8% and Class-II positive cells between 22.8% and 32.2%. Interleukin 2 receptor positive cells ranged between 5.5% and 8.5% as detected with AMT-13 monoclonal antibody which recognise the interleukin 2 binding site. A higher percentage of activated cells was observed using another monoclonal antibody (7D4) directed against a different epitope of the interleukin 2 receptor, suggesting the presence of activated lymphocytes with interleukin 2 receptors saturated by interleukin 2. No insulin-containing cells were found to express Class-II molecules as demonstrated by a double immunofluorescence technique. Most infiltrating mononuclear cells were found to be positive for Class-II and L3T4 antigens or to be Class-II positive and express surface immunoglobulins.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal induction of allogeneic tolerance prevents T cell-mediated autoimmunity in NOD mice

Diabetes in the NOD mouse strain is a genetically programmed T cell-mediated autoimmune process that is directed against an as yet unknown antigen target(s) on pancreatic beta cells. To investigate whether the course of the autoimmune disease could be altered by immune manipulations of the T cell repertoire, we have induced allogeneic tolerance by injecting F1 semiallogeneic spleen cells into NOD neonates. This procedure resulted in a significant protection against both insulitis and diabetes. However, although it requires the induction of tolerance, as shown by the failure of non-tolerizing irradiated cells to prevent autoimmunity, protection appeared to be independent of the major histocompatibility complex haplotypes of the F1 spleen cells injected at birth, e.g. (C57BL/6 x NOD)F1, (CBA/Ca x NOD)F1 or (BALB/c x NOD)F1 cells. In addition, a similar degree of protection was induced, whether the tolerant state, as assessed by mixed lymphocyte reaction studies in vitro, was of short duration, approximately 6 weeks, or lasted for more than 12 weeks. Putative veto or suppressor functions of chimeric T cells were ruled out, since mice tolerized with T cell-depleted F1 spleen cells were equally protected. We conclude that the expression of spontaneous T cell-mediated autoimmunity can be modulated by immune manipulations at birth. Whether the protection observed in the present experiments resulted from the production of one or several specific holes in the autoimmune T cell repertoire, i.e. cross-tolerance, or whether it resulted from nonspecific disturbances of the emerging T cell repertoire remains to be elucidated.

Restriction fragment length polymorphism analysis of major histocompatibility complex genes in the non-obese diabetic mouse strain and its non-diabetic sister strains

It has been suggested that one of the recessive genes controlling diabetes in non-obese diabetic mice is linked to the major histocompatibility complex. We, therefore, performed restriction fragment length polymorphism studies of major histocompatibility complex genes (class I, II, and III) in non-obese diabetic mice in comparison with those of their non-diabetic sister strains, non-obese non-diabetic, cataract, and ILI mice which were derived from the same Jcl-ICR mice as the non-obese diabetic mouse was. When class II and III probes and a minimum of four restriction enzymes were used, class II and III genes of non-obese diabetic mice were indistinguishable from those of cataract and ILI mice but totally different from those of non-obese non-diabetic mice. The studies also indicated that A beta, E beta, and C4-Slp genes of non-obese diabetic, cataract, and ILI mice, and A alpha, A beta, E beta and C4-Slp genes of non-obese non-diabetic mice are different from those of BALB/c and C57BL/6 mice, respectively. While non-obese non-diabetic mice expressed the E alpha gene, non-obese diabetic, cataract, and ILI mice appeared to carry a deletion in the 5' end of the E alpha gene resulting in failure to transcribe the E alpha gene. When class I probe was used, cataract mice showed very different band patterns from those of the other ICR-derived mice. It is suggested that non-obese diabetic, non-obese non-diabetic, and ILI mice contain only a single class I D region gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Inherited diseases in North American Mennonites: focus on Old Colony (Chortitza) Mennonites

The patterns of migration and the genetic disorders occurring among North American Mennonites are reviewed, and inherited conditions recently recognized in a religious and genetic isolate, the Old Colony (Chortitza) Mennonites, are described. Old Colony Mennonites are of Dutch/German origin and descend from approximately 400 founding families who settled in the Old Colony, Chortitza (the Ukraine, USSR) in the late 1700s, and then migrated to Canada and Central and South America in the past century. We investigated over 6 generations of a Canadian Old Colony kindred in which there was extensive intermarriage, and in whom 28 individuals developed diabetes mellitus. Insulin-dependent diabetes mellitus (IDDM) occurred in 14 affected individuals in 10 closely related sibships; the 11 living IDDM patients were all concordant for the immunogenetic marker HLA-DR4. Fourteen close relatives had other disorders of carbohydrate metabolism, including gestational diabetes and non-insulin-dependent diabetes mellitus. Other close relatives had autoimmune diseases, including rheumatoid arthritis, hyper- and hypothyroidism, multiple sclerosis, and red cell aplasia. Other inherited diseases, including Alport syndrome, congenital defects, and inborn errors of metabolism were also found in the kindred. In the almost exclusively (99%) Old Colony Mennonite public health district in which the kindred was ascertained, there were multiple cases of Tourette syndrome, of malformations (including congenital heart defects and cleft lip +/- palate), and familial clusters of inborn errors of metabolism. We report this Old Colony (Chortitza) Mennonite isolate because 1) there are large familial aggregations of tissue-specific autoimmune diseases, malformations, inborn errors of metabolism, and of some other conditions whose genetic basis is still unknown; 2) there are multiple cases of rare genetic conditions, 3) we have established a computerized genealogic data base on over 1,000 kindred members as well as a cryopreserved lymphocyte/DNA bank on over 100 closely related individuals with various genetic conditions; and 4) this religious isolate, which extends across North, Central, and South America, offers an excellent opportunity for studying the epidemiology and molecular genetics of both common and rare inherited diseases.

Immunological aspects of diabetes mellitus: prospects for pharmacological modification

It is now well known that insulin-dependent diabetes is a chronic progressive autoimmune disease. The prolonged prediabetic phase of progressive beta-cell dysfunction is associated with immunological abnormalities. A prediabetic period is suggested by the appearance of islet cell antibodies, anti-insulin antibodies, and anti-insulin receptor antibodies. The existence of activated T lymphocytes and abnormal T cell subsets are also other markers. There is still no concensus about the use of the immunosuppression superimposed upon conventional insulin therapy in early diagnosed IDDM and the follow-up of the relatives of IDDM patients who share the genetic predisposition and serological markers for the risk of future onset of IDDM. Treatment in the prodromal period cannot be justified because a link between the disease and early markers such as ICA has not been established with certainty (Diabetes Research Program NIH, 1983). Many immunopharmacological manipulations were reported to be effective in animal models. However, most of them are not readily applied to human subjects. Moreover, IDDM patients are now believed to be heterogeneous, with a complex genetic background. HLA-DR, and more recently DQ, are closely related to the genetic predisposition to IDDM but those genes are not themselves diabetogenic. The contribution of autoimmunity does not appear to be uniform, and in some cases, the contribution of virus is considered more important. There is a lack of a marker for the future onset of IDDM. ICA and ICSA were found after mumps infection, but the existence of those autoantibodies and even the co-existence of HLA-DR3 do not always indicate the future trend to insulin dependency. More precise markers will be disclosed through the biochemical analysis of the target antigens on pancreatic beta-cell for islet antibodies and effector T cells. Much safer and more effective immunopharmacological treatment will be developed through animal experimentation using rat and mouse models. The recent development and interest in this field will further facilitate the attainment of the goal for the complete prevention of IDDM.

Combined segregation and linkage analysis for IDDM and HLA-DR under several ascertainment assumptions

Combined segregation and linkage analysis of the Genetic Analysis Workshop 5 (GAW5) data suggests a complex basis for susceptibility to insulin-dependent diabetes mellitus (IDDM). One susceptibility gene, linked to the HLA-DR region, is additive on the liability scale (d = .49 +/- .15, t = 2.9 +/- .6) with a gene frequency q = .30 +/- .03. A second locus, with a gene frequency of q = .07 +/- .02, which is recessive and unlinked to HLA, is also suggested by the analysis. The ascertainment correction used has little effect on the results, presumably because most of the information comes from the cosegregation of HLA alleles and disease status. The results are consistent with a direct involvement of the HLA-DR region in susceptibility, but are not a proof of it.

Molecular characterization of MHC class II antigens (beta 1 domain) in the BB diabetes-prone and -resistant rat

The BB or BB/Worcester (BB/W) rat is widely recognized as a model for human insulin-dependent diabetes mellitus (IDDM). Of at least three genes implicated in genetic susceptibility to IDDM in this strain, one is clearly linked to the major histocompatibility complex (MHC). In an attempt to define the diabetogenic gene(s) linked to the MHC of the BB rat, cDNA clones encoding the class II MHC gene products of the BB diabetes-prone and diabetes-resistant sublines have been isolated and sequenced. For comparison, the beta 1 domain of class II genes of the Lewis rat (RT1L) were sequenced. Analysis of the sequence data reveals that the first domain of RT1.D beta and RT1.B beta chain of the BB rat are different from other rat or mouse class II sequences. However, these sequences were identical in both the BB diabetes-prone and BB diabetes-resistant sublines. The significance of these findings is discussed in relation to MHC class II sequence data in IDDM patients and in the nonobese diabetic (NOD) mouse strain.