A genetic variant of the protein tyrosine phosphatase non-receptor 22 (PTPN22) is associated with a wide range of autoimmune diseases; however, the reasons behind its prevalence in the general ...population remain not completely understood. Recent evidence highlights an important role of autoimmune susceptibility genetic variants in conferring resistance against certain pathogens. In this study, we examined the role of PTPN22 in persistent infection in mice lacking PTPN22 infected with lymphocytic choriomeningitis virus clone 13. We found that lack of PTPN22 in mice resulted in viral clearance 30 days after infection, which was reflected in their reduced weight loss and overall improved health. PTPN22
mice exhibited enhanced virus-specific CD8 and CD4 T cell numbers and functionality and reduced exhausted phenotype. Moreover, mixed bone marrow chimera studies demonstrated no differences in virus-specific CD8 T cell accumulation and function between the PTPN22
and PTPN22
compartments, showing that the effects of PTPN22 on CD8 T cells are T cell-extrinsic. Together, these findings identify a CD8 T cell-extrinsic role for PTPN22 in weakening early CD8 T cell responses to collectively promote persistence of a chronic viral infection.
Type 1 diabetes (T1D) is an autoimmune disease caused by the lack of insulin-producing pancreatic beta cells leading to systemic hyperglycemia. Pancreatic islet transplantation is a valid therapeutic ...approach to restore insulin loss and to promote adequate glycemic control. Pancreatic islet transplantation in mice is an optimal preclinical model to identify new therapeutic strategies aiming at preventing rejection and optimizing post-transplant immuno-suppressive/-tolerogenic therapies. Islet transplantation in preclinical animal models can be performed in different sites such the kidney capsule, spleen, bone marrow and pancreas. This protocol describes murine islet transplantation under the kidney capsule. This is a widely accepted procedure for research purposes. Stress caused in the animals is minimal and it leads to reliable and reproducible results.
Term and preterm neonates have very few circulating Tfh‐like cells (cTfh), and no circulating Tfr‐like cells. Neonatal cTfh are CXCR5loPD‐1loCD45RAhi, suggestive of a naive, possibly recently ...activated phenotype. CXCL13 is high at birth, but decreases rapidly in the first weeks of life. Overall, signs of GC activity in human neonates are weak, even in those born prematurely or after sepsis.
Abstract
Adoptive regulatory T‐cell (Treg) transfer has emerged as a promising therapeutic strategy for regulating immune responses in organ transplantation, graft versus host disease, and ...autoimmunity, including Type 1 diabetes. Traditionally, Treg for adoptive therapy have been sorted and expanded in vitro using high doses of IL‐2, demonstrating stability and suppressive capabilities. However, limitations in their long‐term survival post‐infusion into patients have been observed. To address this challenge, we investigated a novel expansion protocol incorporating interleukin‐7 (IL‐7) alongside the traditional method utilizing IL‐2 (referred to as IL‐7 method, IL‐7M). Our study revealed that naïve Treg express significant levels of CD127 and display robust responsiveness to IL‐7, characterized by STAT‐5 phosphorylation. Expanding naïve Treg with the IL‐7M protocol led to a substantial enrichment of CD45RA
+
CD62L
+
CD95
+
Treg but showing a reduction in the final cell yield and suppressive function. Moreover, Treg expanded with the IL‐7M exhibited preserved telomere length and demonstrated enhanced resistance to cytokine withdrawal and fas‐mediated apoptosis. When transferred into NSG mice IL‐7M‐Treg persisted longer and reduced the expansion of T cells, but did not significantly reduce the severity of xenoGvHD. In conclusion, our data demonstrate the feasibility of expanding naïve Treg in the presence of IL‐7 to generate a Treg product enriched in poorly differentiated CD45RA
+
cells with enhanced survival capabilities.
The aim of this study was to characterize the immune response against intrabone marrow (BM-Tx) or intraliver (liver-Tx) transplanted islets in the presence or in the absence of immunosuppression.
...Less (C57BL/6 in Balb/c) and highly (Balb/c in C57BL/6) stringent major histocompatibility complex fully mismatched mouse models were used to evaluate the alloimmune response. Single antigen-mismatched mouse model (C57BL/6 RIP-GP in C57BL/6) was used to evaluate the antigen-specific immune response. Mice received tacrolimus (FK-506, 0.1 mg/kg per day)/mycophenolate mofetil (MMF, 60 mg/kg per day), and anti-CD3 (50 μg/day) either alone or in combination.
Transplant site did not impact the timing nor the kinetics of the alloimmune and single antigen-specific memory T cell responses in the absence of immunosuppression or in the presence of MMF/FK-506 combination. On the other hand, the median time to graft rejection was 28 ± 5.2 days and 16 ± 2.6 days (P = 0.14) in the presence of anti-CD3 treatment, 50 ± 12.5 days and 10 ± 1.3 days (P = 0.003) in the presence of anti-CD3/MMF/FK-506 treatment for liver-Tx and BM-Tx, respectively. Anti-CD3 did not differentially reach BM and liver tissues but was more effective in reducing graft associated T cell responses in liver-Tx than in BM-Tx.
Islets infused in the BM appear less protected from the adaptive immune response in the presence of the anti-CD3 treatment. This result raises some concerns over the potential of the BM as a site for islet allotransplantation.
Type 1 regulatory T (Tr1) cells are an inducible subset of CD4+ Tr cells characterized by high levels of interleukin (IL)-10 production and regulatory properties. Several protocols to generate human ...Tr1 cells have been developed in vitro. However, the resulting population includes a significant fraction of contaminating non-Tr1 cells, representing a major bottleneck for clinical application of Tr1 cell therapy. We generated an homogeneous IL-10–producing Tr1 cell population by transducing human CD4+ T cells with a bidirectional lentiviral vector (LV) encoding for human IL-10 and the marker gene, green fluorescent protein (GFP), which are independently coexpressed. The resulting GFP+ LV-IL-10–transduced human CD4+ T (CD4LV-IL-10) cells expressed, upon T-cell receptor (TCR) activation, high levels of IL-10 and concomitant low levels of IL-4, and markers associated with IL-10. Moreover, CD4LV-IL-10 T cells displayed typical Tr1 features: the anergic phenotype, the IL-10, and transforming growth factor (TGF)-β dependent suppression of allogeneic T-cell responses, and the ability to suppress in a cell-to-cell contact independent manner in vitro. CD4LV-IL-10 T cells were able to control xeno graft-versus-host disease (GvHD), demonstrating their suppressive function in vivo. These results show that constitutive over-expression of IL-10 in human CD4+ T cells leads to a stable cell population that recapitulates the phenotype and function of Tr1 cells.
In the attempt to understand the origin of autoantibody (AAb) production in patients with and at risk for type 1 diabetes (T1D), multiple studies have analyzed and reported alterations in T ...follicular helper (Tfh) cells in presymptomatic AAb
subjects and patients with T1D. Yet, whether the regulatory counterpart of Tfh cells, represented by T follicular regulatory (Tfr) cells, is similarly altered is still unclear. To address this question, we performed analyses in peripheral blood, spleen, and pancreatic lymph nodes (PLN) of organ donor subjects with T1D. Blood analyses were also performed in living AAb
and AAb
subjects. While negligible differences in the frequency and phenotype of blood Tfr cells were observed among T1D, AAb
, and AAb
adult subjects, the frequency of Tfr cells was significantly reduced in spleen and PLN of T1D as compared with nondiabetic control subjects. Furthermore, adoptive transfer of Tfr cells delayed disease development in a mouse model of T1D, a finding that could indicate that Tfr cells play an important role in peripheral tolerance and regulation of autoreactive Tfh cells. Together, our findings provide evidence of Tfr cell alterations within disease-relevant tissues in patients with T1D, suggesting a role for Tfr cells in defective humoral tolerance and disease pathogenesis.
Aims/hypothesis
Islet autoantibodies (AAbs) are detected in >90% of individuals with clinically suspected type 1 diabetes at disease onset. A single AAb, sometimes at low titre, is often detected in ...some individuals, making their diagnosis uncertain. Type 1 diabetes genetic risk scores (GRS) are a useful tool for discriminating polygenic autoimmune type 1 diabetes from other types of diabetes, particularly the monogenic forms, but testing is not routinely performed in the clinic. Here, we used a type 1 diabetes GRS to screen for monogenic diabetes in individuals with weak evidence of autoimmunity, i.e. with a single AAb at disease onset.
Methods
In a pilot study, we genetically screened 142 individuals with suspected type 1 diabetes, 42 of whom were AAb-negative, 27 of whom had a single AAb (single AAb-positive) and 73 of whom had multiple AAbs (multiple AAb-positive) at disease onset. Next-generation sequencing (NGS) was performed in 41 AAb-negative participants, 26 single AAb-positive participants and 60 multiple AAb-positive participants using an analysis pipeline of more than 200 diabetes-associated genes.
Results
The type 1 diabetes GRS was significantly lower in AAb-negative individuals than in those with a single and multiple AAbs. Pathogenetic class 4/5 variants in MODY or monogenic diabetes genes were identified in 15/41 (36.6%) AAb-negative individuals, while class 3 variants of unknown significance were identified in 17/41 (41.5%). Residual C-peptide levels at diagnosis were higher in individuals with mutations compared to those without pathogenetic variants. Class 3 variants of unknown significance were found in 11/26 (42.3%) single AAb-positive individuals, and pathogenetic class 4/5 variants were present in 2/26 (7.7%) single AAb-positive individuals. No pathogenetic class 4/5 variants were identified in multiple AAb-positive individuals, but class 3 variants of unknown significance were identified in 19/60 (31.7%) patients. Several patients across the three groups had more than one class 3 variant.
Conclusions/interpretation
These findings provide insights into the genetic makeup of patients who show weak evidence of autoimmunity at disease onset. Absence of islet AAbs or the presence of a single AAb together with a low type 1 diabetes GRS may be indicative of a monogenic form of diabetes, and use of NGS may improve the accuracy of diagnosis.
Graphical abstract
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