Protocol to characterize the melanoma tumor immune microenvironment in mice from single cell to flow cytometry analysis

Here, we present a protocol to study and describe immune cells that surround or infiltrate tumor cells or get through the body of a melanoma syngeneic mice model. We describe steps for creating and establishing the syngeneic mouse model, euthanasia, and tumor or organ harvest. We then detail procedures to rapidly achieve a single-cell suspension from different tissue samples to further quantify and analyze the phenotype of the immune cell population (lymphocytes T and B, tumor-associated macrophages, and myeloid-derived suppressor cells) by flow cytometry.

Mutual modulation of gut microbiota and the immune system in type 1 diabetes models

The transgenic 116C-NOD mouse strain exhibits a prevalent Th17 phenotype, and reduced type 1 diabetes (T1D) compared to non-obese diabetic (NOD) mice. A cohousing experiment between both models revealed lower T1D incidence in NOD mice cohoused with 116C-NOD, associated with gut microbiota changes, reduced intestinal permeability, shifts in T and B cell subsets, and a transition from Th1 to Th17 responses. Distinct gut bacterial signatures were linked to T1D in each group. Using a RAG-2-/- genetic background, we found that T cell alterations promoted segmented filamentous bacteria proliferation in young NOD and 116C-NOD, as well as in immunodeficient NOD.RAG-2-/- and 116C-NOD.RAG-2-/- mice across all ages. Bifidobacterium colonization depended on lymphocytes and thrived in a non-diabetogenic environment. Additionally, 116C-NOD B cells in 116C-NOD.RAG-2-/- mice enriched the gut microbiota in Adlercreutzia and reduced intestinal permeability. Collectively, these results indicate reciprocal modulation between gut microbiota and the immune system in rodent T1D models.

NOD mouse dorsal root ganglia display morphological and gene expression defects before and during autoimmune diabetes development

Introduction

During the development of Autoimmune Diabetes (AD) an autoimmune attack against the Peripheral Nervous System occurs. To gain insight into this topic, analyses of Dorsal Root Ganglia (DRG) from Non-Obese Diabetic (NOD) mice were carried out.

Methods

Histopathological analysis by electron and optical microscopy in DRG samples, and mRNA expression analyzes by the microarray technique in DRG and blood leukocyte samples from NOD and C57BL/6 mice were performed.

Results

The results showed the formation of cytoplasmic vacuoles in DRG cells early in life that could be related to a neurodegenerative process. In view of these results, mRNA expression analyses were conducted to determine the cause and/or the molecules involved in this suspected disorder. The results showed that DRG cells from NOD mice have alterations in the transcription of a wide range of genes, which explain the previously observed alterations. In addition, differences in the transcription genes in white blood cells were also detected.

Discussion

Taken together, these results indicate that functional defects are not only seen in beta cells but also in DRG in NOD mice. These results also indicate that these defects are not a consequence of the autoimmune process that takes place in NOD mice and suggest that they may be involved as triggers for its development.

A new platform for autoimmune diseases. Inducing tolerance with liposomes encapsulating autoantigens

Autoimmune diseases (AIDs) are caused by the loss of self-tolerance and destruction of tissues by the host's immune system. Several antigen-specific immunotherapies, focused on arresting the autoimmune attack, have been tested in clinical trials with discouraging results. Therefore, there is a need for innovative strategies to restore self-tolerance safely and definitively in AIDs. We previously demonstrated the therapeutic efficacy of phosphatidylserine (PS)-liposomes encapsulating autoantigens in experimental type 1 diabetes and multiple sclerosis. Here, we show that PS-liposomes can be adapted to other autoimmune diseases by simply replacing the encapsulated autoantigen. After administration, they are distributed to target organs, captured by phagocytes and interact with several immune cells, thus exerting a tolerogenic and immunoregulatory effect. Specific PS-liposomes demonstrate great preventive and therapeutic efficacy in rheumatoid arthritis and myasthenia gravis. Thus, this work highlights the therapeutic potential of a platform for several autoimmunity settings, which is specific, safe, and with long-term effects.

Inflammation targets CDK11 in autoimmune diabetes as a protective mechanism against beta cell apoptosis

Autoimmune diabetes (T1D) is caused by the immune-mediated destruction of insulin-producing beta cells in the pancreas leading to hyperglycemia. Apoptosis is the main mechanism responsible for beta cell demise, including Fas-receptor engagement and Perforin release as essential death executers. However, the chronic inflammatory milieu pervading pancreatic islets prior to diabetes onset, alters beta cells function and primes beta cells for apoptosis long before the debut of the disease. To identify those genes that are targeted by inflammation and are causally related to beta cell fitness and viability we have used the microarray technology. We have identified several candidate genes being downregulated by inflammation, one of this genes is Cdk11, a cyclin-dependent kinase which is involved in transcription (CDK11p130), mitosis and apoptosis (CDK11p58). L-type cyclins are the partners for Cdk11p130, and Cyclin D3 is the partner of CDK11p58. The Cdk11 gene, when is transcribed, generates a single mRNA form, that can be translated either into CDK11p130 or CDK11p58 by a differential IRES (Internal Ribosome Entry Site) usage, being CDK11p58 only expressed during mitosis, while CDK11p130is expressed during all cell cycle phases. We have addressed the role of CDK11 in autoimmune diabetes using the T1D-prone NOD mouse model hemideficient in CDK11, since the CDK11 null mutation is embryonically lethal. First of all, we have confirmed the effect of inflammation on Cdk11 mRNA expression in islet cells by submitting NODSCID mice to adoptive transfer of increasing amounts of diabetogenic NOD splenocytes, and, observed that Cdk11 expression in islet endocrine cells is downregulated by inflammation in a dose-response dependent manner.

CDK11 Promotes Cytokine-Induced Apoptosis in Pancreatic Beta Cells Independently of Glucose Concentration and Is Regulated by Inflammation in the NOD Mouse Model

Background

Pancreatic islets are exposed to strong pro-apoptotic stimuli: inflammation and hyperglycemia, during the progression of the autoimmune diabetes (T1D). We found that the Cdk11(Cyclin Dependent Kinase 11) is downregulated by inflammation in the T1D prone NOD (non-obese diabetic) mouse model. The aim of this study is to determine the role of CDK11 in the pathogenesis of T1D and to assess the hierarchical relationship between CDK11 and Cyclin D3 in beta cell viability, since Cyclin D3, a natural ligand for CDK11, promotes beta cell viability and fitness in front of glucose.

Methods

We studied T1D pathogenesis in NOD mice hemideficient for CDK11 (N-HTZ), and, in N-HTZ deficient for Cyclin D3 (K11HTZ-D3KO), in comparison to their respective controls (N-WT and K11WT-D3KO). Moreover, we exposed pancreatic islets to either pro-inflammatory cytokines in the presence of increasing glucose concentrations, or Thapsigargin, an Endoplasmic Reticulum (ER)-stress inducing agent, and assessed apoptotic events. The expression of key ER-stress markers (Chop, Atf4 and Bip) was also determined.

Results

N-HTZ mice were significantly protected against T1D, and NS-HTZ pancreatic islets exhibited an impaired sensitivity to cytokine-induced apoptosis, regardless of glucose concentration. However, thapsigargin-induced apoptosis was not altered. Furthermore, CDK11 hemideficiency did not attenuate the exacerbation of T1D caused by Cyclin D3 deficiency.

Conclusions

This study is the first to report that CDK11 is repressed in T1D as a protection mechanism against inflammation-induced apoptosis and suggests that CDK11 lies upstream Cyclin D3 signaling. We unveil the CDK11/Cyclin D3 tandem as a new potential intervention target in T1D.

Characterisation of the inflammatory response triggered by topical ingenol mebutate 0.05% gel in basal cell carcinoma

BACKGROUND/OBJECTIVE

Ingenol mebutate gel is approved for actinic keratosis field therapy, but little has been published as a treatment of basal cell carcinoma (BCC). Our objective is to characterise the histopathological changes and the infiltrating cell populations to better understand its mechanism of action.

METHODS

Sixteen patients with various BCC subtypes were prospectively evaluated and treated once daily for two consecutive days with ingenol mebutate gel 0.05% under occlusion. Patients were randomised to two arms: the first arm was biopsied between the third and the tenth day after treatment initiation ('early immune response'), and the second arm was biopsied at day 30 after treatment initiation ('late immune response'). The immunopathology was evaluated by immunohistochemistry: anti-CD3, anti-CD4, anti-CD8, anti-CD20, anti-CD56, anti-CD68, anti-Bcl-2, anti-CASP3, anti-FoxP3, anti-GrzB and anti-TIA-1.

RESULTS

Ten BCCs were in complete remission after 2 years of follow-up. The early immune response was characterised by a quick recruitment of T lymphocytes, macrophages and natural killer cells. At later time-points, T-regulatory cells and some pro-apoptotic markers were detected. Treatment-related adverse events were described.

CONCLUSION

Ingenol mebutate gel produces a transient immuno-inflammatory response and an important necrosis reaction in BCCs. Larger studies will be required to determine the maximum effective tolerated dose of ingenol mebutate gel for BCC.

Repurposed Analog of GLP-1 Ameliorates Hyperglycemia in Type 1 Diabetic Mice Through Pancreatic Cell Reprogramming

Type 1 diabetes is an autoimmune disease caused by the destruction of the insulin-producing β-cells. An ideal immunotherapy should combine the blockade of the autoimmune response with the recovery of functional target cell mass. With the aim to develop new therapies for type 1 diabetes that could contribute to β-cell mass restoration, a drug repositioning analysis based on systems biology was performed to identify the β-cell regenerative potential of commercially available compounds. Drug repositioning is a strategy used for identifying new uses for approved drugs that are outside the scope of the medical indication. A list of 28 non-synonymous repurposed drug candidates was obtained, and 16 were selected as diabetes mellitus type 1 treatment candidates regarding pancreatic β-cell regeneration. Drugs with poor safety profile were further filtered out. Lastly, we selected liraglutide for its predictive efficacy values for neogenesis, transdifferentiation of α-cells, and/or replication of pre-existing β-cells. Liraglutide is an analog of glucagon-like peptide-1, a drug used in patients with type 2 diabetes. Liraglutide was tested in immunodeficient NOD-Scid IL2rg^-/- (NSG) mice with type 1 diabetes. Liraglutide significantly improved the blood glucose levels in diabetic NSG mice. During the treatment, a significant increase in β-cell mass was observed due to a boost in β-cell number. Both parameters were reduced after withdrawal. Interestingly, islet bihormonal glucagon⁺insulin⁺ cells and insulin⁺ ductal cells arose during treatment. In vitro experiments showed an increase of insulin and glucagon gene expression in islets cultured with liraglutide in normoglycemia conditions. These results point to β-cell replacement, including transdifferentiation and neogenesis, as aiding factors and support the role of liraglutide in β-cell mass restoration in type 1 diabetes. Understanding the mechanism of action of this drug could have potential clinical relevance in this autoimmune disease.

B-Lymphocyte Phenotype Determines T-Lymphocyte Subset Differentiation in Autoimmune Diabetes

Previous studies indicate that B-lymphocytes play a key role activating diabetogenic T-lymphocytes during the development of autoimmune diabetes. Recently, two transgenic NOD mouse models were generated: the NOD-PerIg and the 116C-NOD mice. In NOD-PerIg mice, B-lymphocytes acquire an activated proliferative phenotype and support accelerated autoimmune diabetes development. In contrast, in 116C-NOD mice, B-lymphocytes display an anergic-like phenotype delaying autoimmune diabetes onset and decreasing disease incidence. The present study further evaluates the T- and B-lymphocyte phenotype in both models. In islet-infiltrating B-lymphocytes (IIBLs) from 116C-NOD mice, the expression of H2-K^d and H2-A^g7 is decreased, whereas that of BAFF, BAFF-R, and TACI is increased. In contrast, IIBLs from NOD-PerIg show an increase in CD86 and FAS expression. In addition, islet-infiltrating T-lymphocytes (IITLs) from NOD-PerIg mice exhibit an increase in PD-1 expression. Moreover, proliferation assays indicate a high capacity of B-lymphocytes from NOD-PerIg mice to secrete high amounts of cytokines and induce T-lymphocyte activation compared to 116C B-lymphocytes. This functional variability between 116C and PerIg B-lymphocytes ultimately results in differences in the ability to shape T-lymphocyte phenotype. These results support the role of B-lymphocytes as key regulators of T-lymphocytes in autoimmune diabetes and provide essential information on the phenotypic characteristics of the T- and B-lymphocytes involved in the autoimmune response in autoimmune diabetes.

Molecular Targets of inflammation in pancreatic endocrine cells in Type 1 Diabetes (T1D)

T1D (Type 1 Diabetes) is an autoimmune disorder caused by the immune-mediated destruction of insulin-producing beta cells in the pancreas. There are direct mechanisms that have been demonstrated to cause final beta cell demise, such as the pathways triggered by Fas engagement and Perforin release. However, focus should be placed on other indirect mechanisms, such as pro-inflammatory cytokines present in the beta cell niche early on, that progressively debilitate and alter beta cells from earlier phases of T1D progression, rendering them as helpless targets of the immune system at the end. Though beta cells may resist adverse stimuli in early phases of the autoimmune process, the complicity of both, direct and indirect deleterious mechanisms, leads to beta cell death. In an effort to identify those indirect mechanisms that chronically besiege beta cells from the T1D-prone NOD mouse model, we used the microarray technology. We have identified several candidate genes the expression of which is altered in the NOD islet prior to T1D onset. Several of these genes are related to cell cycle progression and are downregulated due to the insulitic attack to the islet. One of these genes is cyclin D-3, a Dtype cyclin that interacts with either Cdk4 or Cdk6 to promote G1/S cycle progression. We have reported that cyclin D3 protects beta cells against cytokine-induced apoptosis and is required for proper beta cell function in a cell-cycle independent fashion. Cdk11 is also affected by inflammation in islet cells and is a cyclin-dependent kinase which is involved in transcription, mitosis and apoptosis. The natural partners of Cdk11 are L-type cyclins. We have examined whether the immune function is affected in the relative absence of Cdk11.

Treatment of T1D via optimized expansion of antigen-specific Tregs induced by IL-2/anti-IL-2 monoclonal antibody complexes and peptide/MHC tetramers

Type 1 diabetes can be overcome by regulatory T cells (Treg) in NOD mice yet an efficient method to generate and maintain antigen-specific Treg is difficult to come by. Here, we devised a combination therapy of peptide/MHC tetramers and IL-2/anti-IL-2 monoclonal antibody complexes to generate antigen-specific Treg and maintain them over extended time periods. We first optimized treatment protocols conceived to obtain an improved islet-specific Treg/effector T cell ratio that led to the in vivo expansion and activation of these Treg as well as to an improved suppressor function. Optimized protocols were applied to treatment for testing diabetes prevention in NOD mice as well as in an accelerated T cell transfer model of T1D. The combined treatment led to robust protection against diabetes, and in the NOD model, to a close to complete prevention of insulitis. Treatment was accompanied with increased secretion of IL-10, detectable in total splenocytes and in Foxp3⁻ CD4 T cells. Our data suggest that a dual protection mechanism takes place by the collaboration of Foxp3⁺ and Foxp3⁻ regulatory cells. We conclude that antigen-specific Treg are an important target to improve current clinical interventions against this disease.

Inflammation targets cell-cycle actors at the onset of autoimmune diabetes (T1D) in pancreatic endocrine cells from the NOD mouse model

Prior to the massive beta cell demise that leads to autoimmune diabetes (Type 1 Diabetes or T1D), profound profiling changes are imprinted onto the beta cell by an aggressive pro-inflammatory environment that interferes negatively with cell functionality and viability. Ourgoal is to determine key signaling pathways altered in beta cells by the autoimmune assault that are responsible for T1D progression. To this end we have used the T1D-prone NOD (Non Obese Diabetic) mouse model. We have identified several candidate genes the expression of which is altered in the NOD isletendocrine cells prior to the diabetes onset. Interestingly, several of these genes are related to cell cycle progression and are downregulated due to the insulitic attack to the islet. One of these genes is cyclin D3, a D-type cyclin that complexes with either Cdk4 or Cdk6 topromote G1/S cycle progression. The cyclin D3 promoter has binding sequences to NF-kB. However, we have reported that cyclin D3 protects beta cells against cytokine-induced apoptosis and is required for proper beta cell function in a cell-cycle independent fashion. Cdk11 is also affected by inflammation in islet cells and is a cyclin-dependent kinase which is involved in transcription, mitosis and apoptosis. The natural partners of Cdk11 are L-type cyclins, but cyclin D3 has been reported to interact with Cdk11 too. We have addressed whether cdk11 downregulationis responsible for beta cell death.

Phosphatidylserine-Liposomes Promote Tolerogenic Features on Dendritic Cells in Human Type 1 Diabetes by Apoptotic Mimicry

Type 1 diabetes (T1D) is a metabolic disease caused by the autoimmune destruction of insulin-producing β-cells. With its incidence increasing worldwide, to find a safe approach to permanently cease autoimmunity and allow β-cell recovery has become vital. Relying on the inherent ability of apoptotic cells to induce immunological tolerance, we demonstrated that liposomes mimicking apoptotic β-cells arrested autoimmunity to β-cells and prevented experimental T1D through tolerogenic dendritic cell (DC) generation. These liposomes contained phosphatidylserine (PS)—the main signal of the apoptotic cell membrane—and β-cell autoantigens. To move toward a clinical application, PS-liposomes with optimum size and composition for phagocytosis were loaded with human insulin peptides and tested on DCs from patients with T1D and control age-related subjects. PS accelerated phagocytosis of liposomes with a dynamic typical of apoptotic cell clearance, preserving DCs viability. After PS-liposomes phagocytosis, the expression pattern of molecules involved in efferocytosis, antigen presentation, immunoregulation, and activation in DCs concurred with a tolerogenic functionality, both in patients and control subjects. Furthermore, DCs exposed to PS-liposomes displayed decreased ability to stimulate autologous T cell proliferation. Moreover, transcriptional changes in DCs from patients with T1D after PS-liposomes phagocytosis pointed to an immunoregulatory prolife. Bioinformatics analysis showed 233 differentially expressed genes. Genes involved in antigen presentation were downregulated, whereas genes pertaining to tolerogenic/anti-inflammatory pathways were mostly upregulated. In conclusion, PS-liposomes phagocytosis mimics efferocytosis and leads to phenotypic and functional changes in human DCs, which are accountable for tolerance induction. The herein reported results reinforce the potential of this novel immunotherapy to re-establish immunological tolerance, opening the door to new therapeutic approaches in the field of autoimmunity.

Assessment of endocrine molecular entities targeted by inflammation that are involved in the onset of autoimmune diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by pancreatic beta cells demise due to the attack of self-lymphocyte repertoire. We aim to identify molecular entities targeted by the autoimmune assault to pancreatic beta cells that are causally related to T1D progression. The proinflammatory biological niche in which beta cells are immersed during the autoimmune insult promotes deep phenotypical changes crucial for the pathogenic process. These changes lead mainly to beta cell fitness impairment, cell cycle intervention and apoptosis triggering.

By using the Microarray technology we identified a series of genes the expression of which is altered in the islet endocrine cells prior to diabetes onset in the NOD (Non Obese Diabetic) mice. One of those genes encodes for cyclin D3 that triggers cell cycle progression through G1 phase towards the S phase. Cyclin D3 can also bind certain transcription factors and activate inflammation process and development of the T cells (NFκB, GATA). The cyclin D3 promoter has binding sequences to NFκB a transcription factor linked to the action of T1D-related proinflammatory cytokines such as IL-1beta and TNFalpha. We found that cyclin D3 is the only D-type cyclin the expression of which is regulated by inflammation in NOD endocrine islet cells. Moreover we found that cyclin D3 protects beta cells against cytokine-induced apoptosis and is required for proper beta cell function. Moreoever, we observed that CDK11, another cell-cycle related gene that interacts with cyclin D3, is also regulated by inflammation in endocrine islet cells. We have assessed whether there is a causal relationship between the coordinated differential expression of both genes during the insulitic assault and diabetes onset

B-lymphocytes expressing an Ig specificity recognizing the pancreatic ß-cell autoantigen peripherin are potent contributors to type 1 diabetes development in NOD mice

While the autoimmune destruction of pancreatic ß-cells underlying type 1 diabetes (1D) development is ultimately mediated by T-cells in NOD mice and also likely humans, B-lymphocytes play an additional key pathogenic role. It appears expression of plasma membrane bound immunoglobulin (Ig) molecules that efficiently capture ß-cell antigens allows autoreactive B-lymphocytes bypassing normal tolerance induction processes to be the subset of antigen presenting cells most efficiently activating diabetogenic T-cells. NOD mice transgenically expressing Ig molecules recognizing antigens that are (insulin) or not (hen egg lysozyme; HEL) expressed by ß-cells have proven useful in dissecting the developmental basis of diabetogenic B-lymphocytes. However, these transgenic Ig specificities were originally selected for their ability to recognize insulin or HEL as foreign, rather than autoantigens. Thus, we generated and characterized NOD mice transgenically expressing an Ig molecule representative of a large proportion of naturally occurring islet-infiltrating B-lymphocytes in NOD mice recognizing the neuronal antigen peripherin. Transgenic peripherin autoreactive B-lymphocytes infiltrate NOD pancreatic islets, acquire an activated proliferative phenotype, and potently support accelerated T1D development. These results support the concept of neuronal autoimmunity as a pathogenic feature of T1D, and targeting such responses could ultimately provide an effective disease intervention approach.

B-cell anergy induces a Th17 shift in a novel B lymphocyte transgenic NOD mouse model, the 116C-NOD mouse

Autoreactive B lymphocytes play a key role as APCs in diaebetogenesis. However, it remains unclear whether B-cell tolerance is compromised in NOD mice. Here, we describe a new B lymphocyte transgenic NOD mouse model, the 116C-NOD mouse, where the transgenes derive from an islet-infiltrating B lymphocyte of a (8.3-NODxNOR) F1 mouse. The 116C-NOD mouse produces clonal B lymphocytes with pancreatic islet beta cell specificity. The incidence of T1D in 116C-NOD mice is decreased in both genders when compared with NOD mice. Moreover, several immune selection mechanisms (including clonal deletion and anergy) acting on the development, phenotype, and function of autoreactive B lymphocytes during T1D development have been identified in the 116C-NOD mouse. Surprisingly, a more accurate analysis revealed that, despite their anergic phenotype, 116C B cells express some costimulatory molecules after activation, and induce a T-cell shift toward a Th17 phenotype. Furthermore, this shift on T lymphocytes seems to occur not only when both T and B cells contact, but also when helper T (Th) lineage is established. The 116C-NOD mouse model could be useful to elucidate the mechanisms involved in the generation of Th-cell lineages.

Characterization of the autoimmune response against the nerve tissue S100β in patients with type 1 diabetes

Type 1 diabetes results from destruction of insulin-producing beta cells in pancreatic islets and is characterized by islet cell autoimmunity. Autoreactivity against non-beta cell-specific antigens has also been reported, including targeting of the calcium-binding protein S100β. In preclinical models, reactivity of this type is a key component of the early development of insulitis. To examine the nature of this response in type 1 diabetes, we identified naturally processed and presented peptide epitopes derived from S100β, determined their affinity for the human leucocyte antigen (HLA)-DRB1*04:01 molecule and studied T cell responses in patients, together with healthy donors. We found that S100β reactivity, characterized by interferon (IFN)-γ secretion, is a characteristic of type 1 diabetes of varying duration. Our results confirm S100β as a target of the cellular autoimmune response in type 1 diabetes with the identification of new peptide epitopes targeted during the development of the disease, and support the preclinical findings that autoreactivity against non-beta cell-specific autoantigens may have a role in type 1 diabetes pathogenesis.

B-lymphocytes expressing an immunoglobulin specificity recognizing the natural pancreatic beta cell autoantigen, peripherin, are rendered proliferatively anergic but still accelerate type 1 diabetes development in NOD mice. (BA3P.107)

Type 1 diabetes (T1D) results from the destruction of insulin-producing pancreatic ß-cells by autoreactive CD4+ and CD8+ T-cells culminating in glucose dysregulation in both humans and the NOD mouse model. It is clear in the NOD mouse model and also likely humans that B-lymphocytes also play a key pathogenic role in T1D. A sizable proportion of B-lymphocytes isolated from pancreatic islets in NOD mice recognize the autoantigen, peripherin, a type II intermediate filament expressed widely in the peripheral and central nervous system. To further understand the role peripherin-reactive B lymphocytes play in the pathogenesis of T1D, we created NOD mice transgenically expressing non-secretory heavy and light chain transgenes encoding an immunoglobulin (Ig) recognizing peripherin derived from islet-associated B lymphocytes. These mice overwhelming produce B-lymphocytes expressing the transgenic peripherin-binding Ig molecule and develop T1D at a significantly accelerated rate compared with the standard NOD strain. Islet infiltration by lymphocytes also occurs earlier in these mice with the vast majority of islet-associated B-lymphocytes expressing the transgenic Ig. While these peripherin-reactive B lymphocytes are diabetogenic, they are also proliferatlively anergic and appear to require frequent replenishment from hematopoietic stem cells. These findings lend credence to the targeting of peripherin autoreactive B-lymphocytes as a possible T1D intervention.

In vivo detection of peripherin-specific autoreactive B cells during type 1 diabetes pathogenesis

Autoreactive B cells are essential for the pathogenesis of type 1 diabetes. The genesis and dynamics of autoreactive B cells remain unknown. In this study, we analyzed the immune response in the NOD mouse model to the neuronal protein peripherin (PRPH), a target Ag of islet-infiltrating B cells. PRPH autoreactive B cells recognized a single linear epitope of this protein, in contrast to the multiple epitope recognition commonly observed during autoreactive B cell responses. Autoantibodies to this epitope were also detected in the disease-resistant NOR and C57BL/6 strains. To specifically detect the accumulation of these B cells, we developed a novel approach, octameric peptide display, to follow the dynamics and localization of anti-PRPH B cells during disease progression. Before extended insulitis was established, anti-PRPH B cells preferentially accumulated in the peritoneum. Anti-PRPH B cells were likewise detected in C57BL/6 mice, albeit at lower frequencies. As disease unfolded in NOD mice, anti-PRPH B cells invaded the islets and increased in number at the peritoneum of diabetic but not prediabetic mice. Isotype-switched B cells were only detected in the peritoneum. Anti-PRPH B cells represent a heterogeneous population composed of both B1 and B2 subsets. In the spleen, anti-PRPH B cell were predominantly in the follicular subset. Therefore, anti-PRPH B cells represent a heterogeneous population that is generated early in life but proliferates as diabetes is established. These findings on the temporal and spatial progression of autoreactive B cells should be relevant for our understanding of B cell function in diabetes pathogenesis.

Latent autoimmune diabetes in adults is perched between type 1 and type 2: evidence from adults in one region of Spain

BACKGROUND

The aim of this study was to characterize the clinical characteristics and insulin secretion in adults with latent autoimmune diabetes in adults (LADA). We also compared these characteristics in subjects with antibody-negative type 2 diabetes (T2DM) or adult-onset type 1 diabetes (T1DM) to subjects with LADA.

METHODS

In this cross-sectional study, 82 patients with LADA, 78 with T1DM and 485 with T2DM were studied. Clinical and metabolic data, in particular those that related to metabolic syndrome, fasting C-peptide and islet-cell autoantibodies [glutamic acid decarboxylase (GADAb) and IA2 (IA2Ab)] were measured.

RESULTS

The frequency of metabolic syndrome in patients with LADA (37.3%) was higher than in those with T1DM (15.5%; p = 0.005) and lower than in patients with T2DM (67.2%; p < 0.001). During the first 36 months of the disease, the C-peptide concentration in LADA patients was higher than in subjects with T1DM but was lower than in T2DM patients (p < 0.01 for comparisons). Glycemic control in LADA patients (HbA1c 8.1%) was worse than in patients with T2DM (HbA1c 7.6%; p =0.007). An inverse association between GADAb titers and C-peptide concentrations was found in subjects with LADA (p < 0.001). Finally, LADA patients rapidly progressed to insulin treatment.

CONCLUSIONS

As in other European populations, patients with LADA in Spain have a distinct metabolic profile compared with patients with T1DM or T2DM. LADA is also associated with higher impairment of beta-cell function and has worse glycemic control than in T2DM. Beta cell function is related to GADAb titers in patients with LADA.

Idd9.1 locus controls the suppressive activity of FoxP3+CD4+CD25+ regulatory T-cells

OBJECTIVE

The approximately 45-cM insulin-dependent diabetes 9 (Idd9) region on mouse chromosome 4 harbors several different type 1 diabetes-associated loci. Nonobese diabetic (NOD) mice congenic for the Idd9 region of C57BL/10 (B10) mice, carrying antidiabetogenic alleles in three different Idd9 subregions (Idd9.1, Idd9.2, and Idd9.3), are strongly resistant to type 1 diabetes. However, the mechanisms remain unclear. This study aimed to define mechanisms underlying the type 1 diabetes resistance afforded by B10 Idd9.1, Idd9.2, and/or Idd9.3.

RESEARCH DESIGN AND METHODS

We used a reductionist approach that involves comparing the fate of a type 1 diabetes-relevant autoreactive CD8(+) T-cell population, specific for residues 206-214 of islet-specific glucose 6 phosphatase catalytic subunit-related protein (IGRP(206-214)), in noncongenic versus B10 Idd9-congenic (Idd9.1 + Idd9.2 + Idd9.3, Idd9.2 + Idd9.3, Idd9.1, Idd9.2, and Idd9.3) T-cell receptor (TCR)-transgenic (8.3) NOD mice.

RESULTS

Most of the protective effect of Idd9 against 8.3-CD8(+) T-cell-enhanced type 1 diabetes was mediated by Idd9.1. Although Idd9.2 and Idd9.3 afforded some protection, the effects were small and did not enhance the greater protective effect of Idd9.1. B10 Idd9.1 afforded type 1 diabetes resistance without impairing the developmental biology or intrinsic diabetogenic potential of autoreactive CD8(+) T-cells. Studies in T- and B-cell-deficient 8.3-NOD.B10 Idd9.1 mice revealed that this antidiabetogenic effect was mediated by endogenous, nontransgenic T-cells in a B-cell-independent manner. Consistent with this, B10 Idd9.1 increased the suppressive function and antidiabetogenic activity of the FoxP3(+)CD4(+)CD25(+) T-cell subset in both TCR-transgenic and nontransgenic mice.

CONCLUSIONS

A gene(s) within Idd9.1 regulates the development and function of FoxP3(+)CD4(+)CD25(+) regulatory T-cells and, in turn, the activation of CD8(+) effector T-cells in the pancreatic draining lymph nodes, without affecting their development or intrinsic diabetogenic potential.

Gene expression profiles for the human pancreas and purified islets in type 1 diabetes: new findings at clinical onset and in long-standing diabetes

Type 1 diabetes (T1D) is caused by the selective destruction of the insulin-producing beta cells of the pancreas by an autoimmune response. Due to ethical and practical difficulties, the features of the destructive process are known from a small number of observations, and transcriptomic data are remarkably missing. Here we report whole genome transcript analysis validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and correlated with immunohistological observations for four T1D pancreases (collected 5 days, 9 months, 8 and 10 years after diagnosis) and for purified islets from two of them. Collectively, the expression profile of immune response and inflammatory genes confirmed the current views on the immunopathogenesis of diabetes and showed similarities with other autoimmune diseases; for example, an interferon signature was detected. The data also supported the concept that the autoimmune process is maintained and balanced partially by regeneration and regulatory pathway activation, e.g. non-classical class I human leucocyte antigen and leucocyte immunoglobulin-like receptor, subfamily B1 (LILRB1). Changes in gene expression in islets were confined mainly to endocrine and neural genes, some of which are T1D autoantigens. By contrast, these islets showed only a few overexpressed immune system genes, among which bioinformatic analysis pointed to chemokine (C-C motif) receptor 5 (CCR5) and chemokine (CXC motif) receptor 4) (CXCR4) chemokine pathway activation. Remarkably, the expression of genes of innate immunity, complement, chemokines, immunoglobulin and regeneration genes was maintained or even increased in the long-standing cases. Transcriptomic data favour the view that T1D is caused by a chronic inflammatory process with a strong participation of innate immunity that progresses in spite of the regulatory and regenerative mechanisms.

Dendritic cells pulsed with antigen-specific apoptotic bodies prevent experimental type 1 diabetes

Dendritic cells (DCs) are powerful antigen-presenting cells capable of maintaining peripheral tolerance. The possibility to generate tolerogenic DCs opens new therapeutic approaches in the prevention or remission of autoimmunity. There is currently no treatment inducing long-term tolerance and remission in type 1 diabetes (T1D), a disease caused by autoimmunity towards beta cells. An ideal immunotherapy should inhibit the autoimmune attack, avoid systemic side effects and allow islet regeneration. Apoptotic cells--a source of autoantigens--are cleared rapidly by macrophages and DCs through an immunologically silent process that contributes to maintaining tolerance. Our aims were to prevent T1D and to evaluate the re-establishment of peripheral tolerance using autologous DCs pulsed in vitro with apoptotic bodies from beta cells. Immature DCs derived from bone marrow of non-obese diabetic (NOD) mice were obtained and pulsed with antigen-specific apoptotic bodies from the beta cell line NIT-1. Those DCs that phagocytosed apoptotic cells diminished the expression of co-stimulatory molecules CD40 and CD86 and reduced secretion of proinflammatory cytokines. Moreover, these cells were resistant to increase the expression of co-stimulatory molecules after lipopolysaccharide activation. The administration of these cells to NOD transgenic mice expressing interferon-beta in their insulin-producing cells, a model of accelerated autoimmune diabetes, decreased diabetes incidence significantly and correlated positively with insulitis reduction. DCs pulsed with apoptotic cells that express disease-associated antigens constitutes a promising strategy to prevent T1D.

Systemic vasculitis associated withFasciola hepaticainfection

We report the case of a 50-year-old man who presented with systemic vasculitis associated with Fasciola hepatica infection. The patient presented with severe skin, kidney, spleen, ophthalmic, and neurological compromise. An immunological examination for primary vasculitis was negative and other infections were discounted by microbiological and serological analyses. The patient was treated with steroids without clinical response. The Fasciola hepatica infection was confirmed by the presence of specific immunoglobulin G (IgG) serum antibodies detected by a quantitative enzyme-linked immunosorbent assay (ELISA) with an optical density (OD) of 0.483 OD units (normal value<0.170 OD units) and a high-titre complement fixation (1/80 dilution). The patient received treatment with triclabendazole and all symptoms and systemic manifestations resolved within weeks. Hence, this previously unreported vasculitis-associated infection, if identified opportunely, can be treated and cured.

Anti-peripherin B lymphocytes are positively selected during diabetogenesis

Rearrangement analysis of immunoglobulin genes is an exceptional opportunity to look back at the B lymphocyte differentiation during ontogeny and the subsequent immune response, and thus to study the selective pressures involved in autoimmune disorders. In a recent study to characterize the antigenic specificity of B lymphocytes during T1D progression, we generated hybridomas of islet-infiltrating B lymphocytes from NOD mice and other related strains developing insulitis, but with different degrees of susceptibility to T1D. We found that a sizable proportion of hybridomas produced monoclonal antibodies reactive to peripherin, an intermediate filament protein mainly found in the peripheral nervous system. Moreover, we found that anti-peripherin antibody-producing hybridomas originated from B lymphocytes that had undergone immunoglobulin class switch recombination, a characteristic of secondary immune response. Therefore, in the present study we performed immunoglobulin VL and VH analysis of these hybridomas to ascertain whether they were derived from B lymphocytes that had undergone antigen-driven selection. The results indicated that whereas some anti-peripherin hybridomas showed signs of oligoclonality, somatic hypermutation and/or secondary rearrangements (receptor edition and receptor revision), others seemed to directly derive from the preimmune repertoire. In view of these results, we conclude that anti-peripherin B lymphocytes are positively selected and primed in the course of T1D development in NOD mice, and reinforce the idea that peripherin is a relevant autoantigen targeted during T1D development in this animal model.

Natural killer cells are required for accelerated type 1 diabetes driven by interferon-beta

The destruction of beta cells by the islet infiltrating lymphocytes causes type 1 diabetes. Transgenic mice models expressing interferon (IFN)-beta in beta cells, in the non-obese diabetic (NOD) strain and in a diabetes-free, major histocompatibility complex-matched, homologous strain, the non-obese resistant (NOR) mice, developed accelerated type 1 diabetes after 3 weeks of age. Our aim was to determine if natural killer (NK) cells could affect the acceleration of the disease. We determined the amount of NK cells in the pancreas, spleen and lymph nodes from NOD rat insulin promoter (RIP)-IFN-beta mice. Pancreatic cytokines were assessed by quantitative real-time polymerase chain reaction and protein arrays. To confirm the relevance of NK cells in the acceleration of autoimmune diabetes this subset was depleted with anti-asialo GM1 antibodies. An increase of intrapancreatic NK cells characterized the accelerated onset of diabetes both in NOD and NOR RIP-IFN-beta transgenic models. Cytokines involved in NK function and migration were found to be hyperexpressed in the pancreas from accelerated diabetic mice. Interestingly, the depletion of NK cells in vivo abolished completely the acceleration of diabetes. NK cells connect innate to adaptive immunity and might play a role in autoimmunity. We report here that NK cells are required critically in the pancreas for accelerated diabetes. This model links inflammation to acceleration of beta cell-specific autoimmunity mediated by NK cells.

Peripherin Is a Relevant Neuroendocrine Autoantigen Recognized by Islet-Infiltrating B Lymphocytes

Most of our knowledge of the antigenic repertoire of autoreactive B lymphocytes in type 1 diabetes (T1D) comes from studies on the antigenic specificity of both circulating islet-reactive autoantibodies and peripheral B lymphocyte hybridomas generated from human blood or rodent spleen. In a recent study, we generated hybridoma cell lines of infiltrating B lymphocytes from different mouse strains developing insulitis, but with different degrees of susceptibility to T1D, to characterize the antigenic specificity of islet-infiltrating B lymphocytes during progression of the disease. We found that many hybridomas produced mAbs restricted to the peripheral nervous system (PNS), thus indicating an active B lymphocyte response against PNS elements in the pancreatic islet during disease development. The aim of this study was to identify the autoantigen recognized by these anti-PNS mAbs. Our results showed that peripherin is the autoantigen recognized by all anti-PNS mAbs, and, therefore, a relevant neuroendocrine autoantigen targeted by islet-infiltrating B lymphocytes. Moreover, we discovered that the immune dominant epitope of this B lymphocyte immune response is found at the C-terminal end of Per58 and Per61 isoforms. In conclusion, our study strongly suggests that peripherin is a major autoantigen targeted during T1D development and poses a new question on why peripherin-specific B lymphocytes are mainly attracted to the islet during disease.

Phenotype and functional characteristics of islet-infiltrating B-cells suggest the existence of immune regulatory mechanisms in islet milieu

B-cells participate in the autoimmune response that precedes the onset of type 1 diabetes, but how these cells contribute to disease progression is unclear. In this study, we analyzed the phenotype and functional characteristics of islet-infiltrating B-cells in the diabetes-prone NOD mouse and in the insulitis-prone but diabetes-resistant (NOD x NOR)F1 mouse. The results indicate that B-cells accumulate in the islets of both mice influenced by sex traits. Phenotypically and functionally, these B-cells are highly affected by the islet inflammatory milieu, which may keep them in a silenced status. Moreover, although islet-infiltrating B-cells seem to be antigen experienced, they can only induce islet-infiltrating T-cell proliferation when they act as accessory cells. Thus, these results strongly suggest that islet-infiltrating B-cells do not activate islet-infiltrating T-cells in situ, although they may affect the progression of the disease otherwise.

Reg (regenerating) gene overexpression in islets from non-obese diabetic mice with accelerated diabetes: role of IFNbeta

AIMS/HYPOTHESIS

The expression of IFNbeta in beta cells results in accelerated type 1 diabetes. The REG family of beta cell proliferation factors have been described as autoantigens in autoimmune diabetes. The aim of this study was to determine the effect of IFNbeta on Reg expression, and the implications of this in terms of autoimmunity.

METHODS

Reg gene expression was determined in islets from non-obese diabetic (NOD) RIP-HuIFNbeta mice by cDNA microarray, quantitative real-time PCR and immunohistochemistry. The effect of IFNbeta on Reg1 and Reg2 expression was assessed in the NOD insulinoma cell line NIT-1. IL-6, known to induce Reg expression, was measured in the insulitis microenvironment. Morphological studies were carried out to determine islet enlargement in this model.

RESULTS

Reg2 was upregulated in islets from the NOD RIP-HuIFNbeta mice at the onset of the autoimmune attack. IFNbeta upregulates Reg1 and Reg2 genes in NIT-1 cells. The expression of Il6 was increased in islets from transgenic mice and in NIT-1 cells exposed to HuIFNbeta. Moreover, islets from transgenic mice were enlarged compared with those from wild-type mice.

CONCLUSIONS/INTERPRETATION

Reg overexpression correlates well with the acceleration of diabetes in this model. The upregulation of Reg suggests that islets try to improve hyperglycaemia by regenerating the cells lost in the autoimmune attack. Reg expression is regulated by several factors such as inflammation. Therefore, the overexpression of an IFNbeta-induced autoantigen (REG) in the islets during inflammation might contribute to the premature onset of diabetes.

Reactogenicity and immunogenicity profile of a two-dose combined hepatitis A and B vaccine in 1-11-year-old children

This study was conducted to compare the reactogenicity, immunogenicity and safety of a combined two-dose (0, 6 months) hepatitis A and B vaccine (720ELU HAV, 20 mcg HBsAg) with the established three-dose (0, 1 and 6 months) hepatitis A and B vaccine (360ELU HAV, 10 mcg HBsAg). A total of 511 children aged 1-11 years who had not previously received a hepatitis A or B vaccine were enrolled in the study. Both vaccines were well tolerated, and were shown to be safe and immunogenic. The analysis, stratified according to two age groups (1-5 year and 6-11-year-old children) demonstrated that the reactogenicity profile of the two-dose schedule was at least as good as that of the established schedule. Both vaccines and schedules provided at least 98% seroprotection against hepatitis B and 100% seroconversion against hepatitis A, 1 month after the end of the vaccination course (Month 7).

IFN beta accelerates autoimmune type 1 diabetes in nonobese diabetic mice and breaks the tolerance to beta cells in nondiabetes-prone mice

Genetic and environmental factors are decisive in the etiology of type 1 diabetes. Viruses have been proposed as a triggering environmental event and some evidences have been reported: type I IFNs exist in the pancreata of diabetic patients and transgenic mice expressing these cytokines in beta cells develop diabetes. To determine the role of IFNbeta in diabetes, we studied transgenic mice expressing human IFNbeta in the beta cells. Autoimmune features were found: MHC class I islet hyperexpression, T and B cells infiltrating the islets and transfer of the disease by lymphocytes. Moreover, the expression of beta(2)-microglobulin, preproinsulin, and glucagon in the thymus was not altered by IFNbeta, thus suggesting that the disease is caused by a local effect of IFNbeta, strong enough to break the peripheral tolerance to beta cells. This is the first report of the generation of NOD (a model of spontaneous autoimmune diabetes) and nonobese-resistant (its homologous resistant) transgenic mice expressing a type I IFN in the islets: transgenic NOD and nonobese-resistant mice developed accelerated autoimmune diabetes with a high incidence of the disease. These results indicate that the antiviral cytokine IFNbeta breaks peripheral tolerance to beta cells, influences the insulitis progression and contributes to autoimmunity in diabetes and nondiabetes- prone mice.

Islet-infiltrating B-cells in nonobese diabetic mice predominantly target nervous system elements

B-cells accumulate in pancreatic islets during the autoimmune response that precedes the onset of type 1 diabetes. However, the role and antigenic specificity of these cells remain a mystery. To elucidate the antigenic repertoire of islet-infiltrating B-cells in type 1 diabetes, we generated hybridoma cell lines of islet-infiltrating B-cells from nonobese diabetic (NOD) mice and NOD mice expressing a diabetogenic T-cell receptor (8.3-NOD). Surprisingly, characterization of the tissue specificity of the antibodies secreted by these cells revealed that a predominant fraction of these hybridomas produce antibodies specific for the pancreatic nervous system. Similar results were obtained with B-cell hybridomas derived from mild insulinic lesions of diabetes-resistant (NOD x NOR)F1 and 8.3-(NOD x NOR)F1 mice. Immunoglobulin class analyses further indicated that most islet-derived hybridomas had arisen from B-cells that had undergone immunoglobulin class switch recombination, suggesting that islet-associated B-cells are involved in active, T-helper-driven immune responses against local antigenic targets. This is the first evidence showing the existence of a predominant active B-cell response in situ against pancreatic nervous system elements in diabetogenesis. Our data are consistent with the idea that this B-cell response precedes the progression of insulitis to overt diabetes, thus strongly supporting the idea that pancreatic nervous system elements are early targets in type 1 diabetes.

Cross-priming of diabetogenic T cells dissociated from CTL-induced shedding of beta cell autoantigens

Cross-presentation of self Ags by APCs is key to the initiation of organ-specific autoimmunity. As MHC class I molecules are essential for the initiation of diabetes in nonobese diabetic (NOD) mice, we sought to determine whether the initial insult that allows cross-presentation of beta cell autoantigens in diabetes is caused by cognate interactions between naive CD8(+) T cells and beta cells. Naive splenic CD8(+) T cells from transgenic NOD mice expressing a diabetogenic TCR killed peptide-pulsed targets in the absence of APCs. To ascertain the role of CD8(+) T cell-induced beta cell lysis in the initiation of diabetes, we expressed a rat insulin promoter (RIP)-driven adenovirus E19 transgene in NOD mice. RIP-E19 expression inhibited MHC class I transport exclusively in beta cells and rendered these cells resistant to lysis by CD8(+) (but not CD4(+)) T cells, both in vitro and in vivo. Surprisingly, RIP-E19 expression impaired the accumulation of CD8(+) T cells in islets and delayed the onset of islet inflammation, without affecting the timing or magnitude of T cell cross-priming in the pancreatic lymph nodes, which is the earliest known event in diabetogenesis. These results suggest that access of beta cell autoantigens to the cross-presentation pathway in diabetes is T cell independent, and reveal a previously unrecognized function of MHC class I molecules on target cells in autoimmunity: local retention of disease-initiating clonotypes.

CD40 ligation releases immature dendritic cells from the control of regulatory CD4+CD25+ T cells

We report that disruption of CD154 in nonobese diabetic (NOD) mice abrogates the helper function of CD4+CD25- T cells without impairing the regulatory activity of CD4+CD25+ T cells. Whereas CD4+ T cells from NOD mice enhanced a diabetogenic CD8+ T cell response in monoclonal TCR-transgenic NOD mice, CD4+ T cells from NOD.CD154(-/-) mice actively suppressed it. Suppression was mediated by regulatory CD4+CD25+ T cells capable of inhibiting CD8+ T cell responses induced by peptide-pulsed dendritic cells (DCs), but not peptide/MHC monomers. It involved inhibition of DC maturation, did not occur in the presence of CD154+ T-helper cells, and could be inhibited by activation of DCs with LPS, CpG DNA, or an agonistic anti-CD40 mAb. Thus, in at least some genetic backgrounds, CD154-CD40 interactions and innate stimuli release immature DCs from suppression by CD4+CD25+ T cells.

Comparison of the reactogenicity and immunogenicity of a combined diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated polio (DTPa-HBV-IPV) vaccine, mixed with the Haemophilus influenzae type b (Hib) conjugate vaccine and administered as a single injection, with the DTPa-IPV/Hib and hepatitis B vaccines administered in two simultaneous injections to infants at 2, 4 and 6 months of age

An open, randomised, multicentre trial was performed to compare the reactogenicity and safety profile of the administration of a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio (DTPa-HBV-IPV) vaccine administered in one injection mixed with Haemophilus influenzae type b (Hib) conjugate vaccine (Group 1) with that of a pentavalent DTPa-IPV vaccine mixed with a Hib vaccine (DTPa-IPV/Hib), simultaneously administered with HBV (Group 2) in two injections in opposite thighs, as a primary vaccination course, to healthy infants at 2, 4 and 6 months of age. A total of 235 completed the study, 120 from Group 1 and 115 from Group 2. Blood samples (pre-vaccination and 1 month after the third dose) were obtained from a subset of infants (Group 1: 40; Group 2: 31) to assess the immune response to vaccination. Local and general solicited symptoms were recorded by parents on diary cards. Seven hundred and five diary cards (Group 1: 360; Group 2: 345) were collected. The clinically relevant and most commonly reported local reaction was pain (infant cried when the limb was moved) in 2.5% (Group 1) and 1.2% (Group 2) of diary cards. Fever was more frequently reported in Group 1 (21% of diary cards) than in Group 2 (12% of diary cards). However only 3 and 2% of doses in Groups 1 and 2, respectively, were responsible for a rectal temperature between 38.6 and 39.5 degrees C and only one case (Group 2) had > or =39.5 degrees C. Other clinically relevant general symptoms were rarely recorded: irritability (2-2.8%), loss of appetite (0.3-0.6%) and drowsiness (0.3-0.3%). All subjects included in the immunogenicity analysis had seroprotective titres to diphtheria, tetanus, polio virus types 1 and 3, Hib. Almost all subjects were seroprotected for anti-polio type 2 and hepatitis B (with the exception of 1 subject in Group 1 for each antigen). The vaccines response rates to pertussis antigens were over 97 and 90% in Groups 1 and 2, respectively. This study shows that, from a clinical perspective, the DTPa-HBV-IPV/Hib vaccine given in a single injection has a similar reactogenicity and safety profile to that of two licensed vaccines (DTPa-IPV/Hib, HBV) given in two simultaneous injections to infants at 2, 4 and 6 months of age. This is a valuable advantage, since in some countries, such as Spain and the UK, an additional injection (for the administration of meningococcal C conjugate vaccine) has been recently included in the infants' vaccination calendars.

CD154-dependent priming of diabetogenic CD4(+) T cells dissociated from activation of antigen-presenting cells

We followed the fate of K(d)- or I-A(g7)-restricted beta cell-autoreactive T cells in monoclonal TCR-transgenic NOD mice expressing or lacking CD154. 8.3-NOD.RAG-2(-/-)/CD154(-/-) mice, which bear autoreactive CD8(+) T cells, developed diabetes with the same incidence and tempo as 8.3-NOD.RAG-2(-/-)/CD154(+) mice. Recruitment of CD154(-/-) 8.3-CD8(+) CTL was accelerated by CD154(+)CD4(+) T cells, by expression of a B7.1 transgene in beta cells or by treatment of the mice with CpG-DNA or an agonistic anti-CD40 antibody. In contrast, the autoreactive CD4(+) T cells maturing in 4.1-NOD.RAG-2(-/-) mice lost their diabetogenic potential if they lacked CD154, even in the presence of CD154(+)CD4(+) T cells, B7.1 molecules on beta cells, CpG-DNA treatment, or systemic CD40 ligation. These results demonstrate the existence of a novel, CD154-dependent pathway of CD4(+) T cell activation that is independent of CD40-mediated activation of APCs.

T-cell tolerance by dendritic cells and macrophages as a mechanism for the major histocompatibility complex-linked resistance to autoimmune diabetes

For poorly understood reasons, the development of autoimmune diabetes in humans and mice is dominantly inhibited by major histocompatibility complex (MHC) class II molecules with diverse antigen-binding sites. We have previously shown that thymocytes expressing a highly diabetogenic I-A(g7)-restricted T-cell receptor (TCR) (4.1-TCR) undergo negative selection in mice carrying one copy of the antidiabetogenic H-2(b) haplotype in an I-A(b)-dependent but superantigen-independent manner. Here, we show that 4.1-TCR-transgenic thymocytes undergo different forms of tolerance in NOD mice expressing antidiabetogenic I-A(d), I-A(g7PD), or I-Ealpha(k) transgenes. The ability of protective MHC class II molecules to induce thymocyte tolerance in 4.1-TCR-transgenic NOD mice correlates with their ability to prevent diabetes in non-TCR-transgenic mice and is associated with polymorphisms within positions 56-67 of their beta1 domains. The 4.1-thymocyte tolerogenic activity of these MHC class II molecules is mediated by dendritic cells and macrophages but not by B-cells or thymic epithelial cells and is a peptide-dependent process. Antidiabetogenic MHC class II molecules may thus afford diabetes resistance by presenting, on dendritic cells and macrophages, tolerogenic peptides to a subset of highly diabetogenic and MHC-promiscuous CD4(+) T-cells that play a critical role in the initiation of diabetes.

Sliding Osteotomies in Mandibular Reconstruction

The aim of this article is to describe a few simple and atraumatic methods for mandibular reconstruction following the ablation of tumors or traumas. These reconstruction techniques are indicated for rebuilding short mandibular defects (less than 4 cm) or for patients in poor general condition with larger defects that cannot be remedied using longer and more complicated procedures. Five types of osteotomies were used: "C," single, double, bilateral sliding, and sagittal sliding. Osteotomies were performed on 14 patients, 13 with malignant tumors and one with a gunshot wound. Good results were obtained in 10 patients, total failure occurred in two, and complications without failure of the reconstruction arose in the other two.

[Clinical features and response to systemic treatment of primary and secondary episcleritis and scleritis resistant to local treatment]

BACKGROUND

Scleritis and episcleritis may extend to adjacent ocular tissues with blinding consequences and may be associated with potentially lethal systemic disorders.

AIM

To evaluate the ocular complications and systemic disease associations of the different types of scleritis and episcleritis.

PATIENTS AND METHODS

Forty six patients with refractory scleritis and episcleritis were studied and treated during the period 1991 to 1998.

RESULTS

Necrotizing type was the most common and severe category in the scleritis group of patients. A decrease in vision occurred in 58.3% of patients with scleritis v/s a 23.5% of patients with epiescleritis (p < 0.05). Uveitis was present in 35.4% of patients with scleritis and scleromalacia was present in 33.3% (p < 0.05). A specific disease association was uncovered in 51% of scleritis and in 38% of episcleritis patients. Rheumatoid arthritis, primary systemic vasculitic disease and Sjögren syndrome with vasculitis were the most common associated systemic diseases. Three patients with scleritis had tuberculosis.

CONCLUSIONS

Scleritis is more severe than episcleritis, and necrotizing scleritis is the most severe type of scleritis. Classification of scleritis and episcleritis provides valuable prognostic information. A meticulous approach for the detection of a specific associated disease must be undertaken. Scleritis associated with vasculitis has a worse ocular prognosis than other non infectious diseases. Cyclophosphamide is the most effective immunosuppressive treatment to control severe ocular involvement.

Progression of autoimmune diabetes driven by avidity maturation of a T-cell population

For unknown reasons, autoimmune diseases such as type 1 diabetes develop after prolonged periods of inflammation of mononuclear cells in target tissues. Here we show that progression of pancreatic islet inflammation to overt diabetes in nonobese diabetic (NOD) mice is driven by the 'avidity maturation' of a prevailing, pancreatic beta-cell-specific T-lymphocyte population carrying the CD8 antigen. This T-lymphocyte population recognizes two related peptides (NRP and NRP-A7) in the context of H-2Kd class I molecules of the major histocompatibility complex (MHC). As pre-diabetic NOD mice age, their islet-associated CD8+ T lymphocytes contain increasing numbers of NRP-A7-reactive cells, and these cells bind NRP-A7/H-2Kd tetramers with increased specificity, increased avidity and longer half-lives. Repeated treatment of pre-diabetic NOD mice with soluble NRP-A7 peptide blunts the avidity maturation of the NRP-A7-reactive CD8+ T-cell population by selectively deleting those clonotypes expressing T-cell receptors with the highest affinity and lowest dissociation rates for peptide-MHC binding. This inhibits the local production of T cells that are cytotoxic to beta cells, and halts the progression from severe insulitis to diabetes. We conclude that avidity maturation of pathogenic T-cell populations may be the key event in the progression of benign inflammation to overt disease in autoimmunity.

IL-1alpha, IL-1beta, and IFN-gamma mark beta cells for Fas-dependent destruction by diabetogenic CD4(+) T lymphocytes

Cytokines such as IL-1alpha, IL-1beta, and IFN-gamma have long been implicated in the pathogenesis of autoimmune diabetes, but the mechanisms through which they promote diabetogenesis remain unclear. Here we show that CD4(+) T lymphocytes propagated from transgenic nonobese diabetic (NOD) mice expressing the highly diabetogenic, beta cell-specific 4.1-T-cell receptor (4.1-TCR) can kill IL-1alpha-, IL-1beta-, and IFN-gamma-treated beta cells from NOD mice. Untreated NOD beta cells and cytokine-treated beta cells from Fas-deficient NOD.lpr mice are not targeted by these T cells. Killing of islet cells in vitro was associated with cytokine-induced upregulation of Fas on islet cells and was independent of MHC class II expression. Abrogation of Fas expression in 4.1-TCR-transgenic NOD mice afforded nearly complete protection from diabetes and did not interfere with the development of the transgenic CD4(+) T cells or with their ability to cause insulitis. In contrast, abrogation of perforin expression did not affect beta cell-specific cytotoxicity or the diabetogenic potential of these T cells. These data demonstrate a novel mechanism of action of IL-1alpha, IL-1beta, and IFN-gamma in autoimmune diabetes, whereby these cytokines mark beta cells for Fas-dependent lysis by autoreactive CD4(+) T cells.

Prevalent CD8(+) T cell response against one peptide/MHC complex in autoimmune diabetes

Spontaneous autoimmune diabetes in nonobese diabetic (NOD) mice is the result of a CD4(+) and CD8(+) T cell-dependent autoimmune process directed against the pancreatic beta cells. CD8(+) T cells play a critical role in the initiation and progression of diabetes, but the specificity and diversity of their antigenic repertoire remain unknown. Here, we define the structure of a peptide mimotope that elicits the proliferation, cytokine secretion, differentiation, and cytotoxicity of a diabetogenic H-2K(d)-restricted CD8(+) T cell specificity (NY8.3) that uses a T cell receptor alpha (TCRalpha) rearrangement frequently expressed by CD8(+) T cells propagated from the earliest insulitic lesions of NOD mice (Valpha17-Jalpha42 elements, often joined by the N-region sequence M-R-D/E). Stimulation of splenic CD8(+) T cells from single-chain 8. 3-TCRbeta-transgenic NOD mice with this mimotope leads to preferential expansion of T cells bearing an endogenously derived TCRalpha chain identical to the one used by their islet-associated CD8(+) T cells, which is also identical to the 8.3-TCRalpha sequence. Cytotoxicity assays using islet-derived CD8(+) T cell clones from nontransgenic NOD mice as effectors and peptide-pulsed H-2K(d)-transfected RMA-S cells as targets indicate that nearly half of the CD8(+) T cells recruited to islets in NOD mice specifically recognize the same peptide/H-2K(d) complex. This work demonstrates that beta cell-reactive CD8(+) T cells mount a prevalent response against a single peptide/MHC complex and provides one peptide ligand for CD8(+) T cells in autoimmune diabetes.

Autoantigen-independent deletion of diabetogenic CD4+ thymocytes by protective MHC class II molecules

Some MHC class II genes provide dominant resistance to certain autoimmune diseases via mechanisms that remain unclear. We have shown that thymocytes bearing a highly diabetogenic, I-Ag7-restricted beta-cell-reactive TCR (4.1-TCR) undergo negative selection in diabetes-resistant H-2g7/x mice by engaging several different antidiabetogenic MHC class II molecules on thymic (but not peripheral) hemopoietic cells, independently of endogenous superantigens. Here we have investigated 1) whether this TCR can also engage protective MHC class II molecules (I-Ab) on cortical thymic epithelial cells in the absence of diabetogenic (I-Ag7) molecules, and 2) whether deletion of 4.1-CD4+ thymocytes in I-Ab-expressing mice might result from the ability of I-Ab molecules to present the target beta-cell autoantigen of the 4.1-TCR. We show that, unlike I-Ag7 molecules, I-Ab molecules can restrict neither the positive selection of 4.1-CD4+ thymocytes in the thymic cortex nor the presentation of their target autoantigen in the periphery. Deletion of 4.1-CD4+ thymocytes by I-Ab molecules in the thymic medulla, however, is a peptide-specific process, since it can be triggered by hemopoietic cells expressing heterogeneous peptide/I-Ab complexes, but not by hemopoietic cells expressing single peptide/I-Ab complexes. Thus, unlike MHC-autoreactive or alloreactive TCRs, which can engage deleting MHC molecules in the thymic cortex, thymic medulla, and peripheral APCs, the 4.1-TCR can only engage deleting MHC molecules (I-Ab) in the thymic medulla. We therefore conclude that this form of MHC-induced protection from diabetes is based on the presentation of an anatomically restricted, nonautoantigenic peptide to highly diabetogenic thymocytes.

Perforin-independent beta-cell destruction by diabetogenic CD8(+) T lymphocytes in transgenic nonobese diabetic mice

Autoimmune diabetes in nonobese diabetic (NOD) mice results from destruction of pancreatic beta cells by T lymphocytes. It is believed that CD8(+) cytotoxic T lymphocytes (CTLs) effect the initial beta-cell insult in diabetes, but the mechanisms remain unclear. Studies of NOD.lpr mice have suggested that disease initiation is a Fas-dependent process, yet perforin-deficient NOD mice rarely develop diabetes despite expressing Fas. Here, we have investigated the role of perforin and Fas in the ability of beta cell-reactive CD8(+) T cells bearing a T-cell receptor (8.3-TCR) that is representative of TCRs used by CD8(+) CTLs propagated from the earliest insulitic lesions of NOD mice, and that targets an immunodominant peptide/H-2Kd complex on beta cells, to effect beta-cell damage in vitro and in vivo. In vitro, 8.3-CTLs killed antigenic peptide-pulsed non-beta-cell targets via both perforin and Fas, but they killed NOD beta cells via Fas exclusively. Perforin-deficient 8.3-TCR-transgenic NOD mice expressing an oligoclonal or monoclonal T-cell repertoire developed diabetes even more frequently than their perforin-competent littermates. These results demonstrate that diabetogenic CD8(+) CTLs representative of CTLs putatively involved in the initiation of autoimmune diabetes kill beta cells in a Fas-dependent and perforin-independent manner.

Two mechanisms for the non-MHC-linked resistance to spontaneous autoimmunity

Genetic susceptibility and resistance to most autoimmune disorders are associated with highly polymorphic genes of the MHC and with non-MHC-linked polygenic modifiers. It is known that non-MHC-linked polymorphisms can override or enhance the susceptibility to an autoimmune disease provided by pathogenic MHC genes, but the mechanisms remain elusive. In this study, we have followed the fate of two highly diabetogenic beta cell-specific T cell receptors (Kd and I-Ag7 restricted, respectively) in NOR/Lt mice, which are resistant to autoimmune diabetes despite expressing two copies of the diabetogenic MHC haplotype H-2g7. We show that at least two mechanisms of non-MHC-linked control of pathogenic T cells operate in these mice. One segregates as a recessive trait and is associated with a reduction in the peripheral frequency of diabetogenic CD8+ (but not CD4+) T cells. The other segregates as a dominant trait and is mediated by IL-4- and TGF-beta1-independent immune suppressive functions provided by lymphocytes that target diabetogenic CD4+ and CD8+ T cells, without causing their deletion, anergy, immune deviation, or ignorance. These results provide explanations as to how non-MHC-linked polymorphisms can override the susceptibility to an autoimmune disease provided by pathogenic MHC haplotypes, and demonstrate that protective non-MHC-linked genes may selectively target specific lymphoid cell types in cellularly complex autoimmune responses.