Chimeric antigen receptor (CAR) T cells targeting a pathogenic MHC class II:peptide complex modulate the progression of autoimmune diabetes (original) (raw)
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Proceedings of the National Academy of Sciences of the United States of America, 2014
The primary autoantigen triggering spontaneous type 1 diabetes mellitus in nonobese diabetic (NOD) mice is insulin. The major T-cell insulin epitope lies within the amino acid 9-23 peptide of the β-chain (B:9-23). This peptide can bind within the peptide binding groove of the NOD MHC class II molecule (MHCII), IA(g7), in multiple positions or "registers." However, the majority of pathogenic CD4 T cells recognize this complex only when the insulin peptide is bound in register 3 (R3). We hypothesized that antibodies reacting specifically with R3 insulin-IA(g7) complexes would inhibit autoimmune diabetes specifically without interfering with recognition of other IA(g7)-presented antigens. To test this hypothesis, we generated a monoclonal antibody (mAb287), which selectively binds to B:9-23 and related variants when presented by IA(g7) in R3, but not other registers. The monoclonal antibody blocks binding of IA(g7)-B:10-23 R3 tetramers to cognate T cells and inhibits T-cell r...
mAbs
Activation of T cells specific for insulin B chain amino acids 9 to 23 (B:9-23) is essential for the initiation of type 1 diabetes (T1D) in non-obese diabetic mice. We previously reported that peptide/MHC complexes containing optimized B:9-23 mimotopes can activate most insulin-reactive pathogenic T cells. A monoclonal antibody (mAb287) targeting these complexes prevented disease in 30-50% of treated animals (compared to 10% of animals given an isotype control). The incomplete protection is likely due to the relatively low affinity of the antibody for its ligand and limited specificity. Here, we report an enhanced reagent, mAb757, with improved specificity, affinity, and efficacy in modulating T1D. Importantly, mAb757 bound with nanomolar affinity to agonists of both "type A" and "type B" cells and suppressed "type B" cells more efficiently than mAb287. When given weekly starting at 4 weeks of age, mAb757 protected ~70% of treated mice from developing T1D for at least 35 weeks, while mAb287 only delayed disease in 25% of animals under the same conditions. Consistent with its higher affinity, mAb757 was also able to stain antigen-presenting cells loaded with B:9-23 mimotopes in vivo. We conclude that monoclonal antibodies that can block the presentation of pathogenic T cell receptor epitopes are viable candidates for antigen-specific immunotherapy for T1D.
Proceedings of the National Academy of Sciences, 2011
In the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D), an insulin peptide (B:9-23) is a major target for pathogenic CD4 + T cells. However, there is no consensus on the relative importance of the various positions or "registers" this peptide can take when bound in the groove of the NOD MHCII molecule, IA g7 . This has hindered structural studies and the tracking of the relevant T cells in vivo with fluorescent peptide-MHCII tetramers. Using mutated B:9-23 peptides and methods for trapping the peptide in particular registers, we show that most, if not all, NOD CD4 + T cells react to B:9-23 bound in low-affinity register 3. However, these T cells can be divided into two types depending on whether their response is improved or inhibited by substituting a glycine for the B:21 glutamic acid at the p8 position of the peptide. On the basis of these findings, we constructed a set of fluorescent insulin-IA g7 tetramers that bind to most insulin-specific Tcell clones tested. A mixture of these tetramers detected a high frequency of B:9-23-reactive CD4 + T cells in the pancreases of prediabetic NOD mice. Our data are consistent with the idea that, within the pancreas, unique processing of insulin generates truncated peptides that lack or contain the B:21 glutamic acid. In the thymus, the absence of this type of processing combined with the low affinity of B:9-23 binding to IA g7 in register 3 may explain the escape of insulin-specific CD4 + T cells from the mechanisms that usually eliminate self-reactive T cells.
European Journal of Immunology, 2010
Polyclonality of self-reactive CD4 1 T cells is the hallmark of several autoimmune diseases like type 1 diabetes. We have previously reported that a soluble dimeric MHC II-peptide chimera prevents and reverses type 1 diabetes induced by a monoclonal diabetogenic T-cell population in double Tg mice [Casares, S. et al., Nat. Immunol. 2002. 3: 383-391]. Since most of the glutamic acid decarboxylase 65 (GAD65)-specific CD4 1 T cells in the NOD mouse are tolerogenic but unable to function in an autoimmune environment, we have activated a silent, monoclonal T-regulatory cell population (GAD65 217-230 -specific CD4 1 T cells) using a soluble I-A ab g7 /GAD65 217-230 /Fcg2a dimer, and measured the effect on the ongoing polyclonal diabetogenic T-cell process. Activated GAD65 217-230 -specific T cells and a fraction of the diabetogenic (B 9-23 -specific) T cells were polarized toward the IL-10secreting T-regulatory type 1-like function in the pancreas of diabetic NOD mice. More importantly, this led to the reversal of hyperglycemia for more than 2 months post-therapy in 80% of mice in the context of stabilization of pancreatic insulitis and improved insulin secretion by the b cells. These findings argue for the stabilization of a polyclonal selfreactive T-cell process by a single epitope-mediated bystander suppression. Dimeric MHC class II-peptide chimeras-like approach may provide rational grounds for the development of more efficient antigen-specific therapies in type 1 diabetes.
Down-regulation of diabetogenic CD4+ T cells by a soluble dimeric peptide–MHC class II chimera
Nature Immunology, 2002
Type 1 diabetes is an organ-specific autoimmune disease that is mediated by autoreactive T cells.We show here that administration of a soluble dimeric peptide-major histocompatibility complex (pMHC) class II chimera (DEF) to prediabetic double-transgenic mice prevents the onset of disease or, in animals that are already diabetic, restores normoglycemia.The antidiabetogenic effects of DEF rely on the induction of anergy in splenic autoreactive CD4 + T cells via alteration of early T cell receptor signaling and stimulation of interleukin 10-secreting T regulatory type 1 cells in the pancreas. Soluble dimeric pMHC class II may be useful in the development of immunospecific therapies for type 1 diabetes.
PLOS ONE, 2013
To develop a vaccination approach for prevention of type 1 diabetes (T1D) that selectively attenuates self-reactive T-cells targeting specific autoantigens, we selected phage-displayed single chain antigen receptor libraries for clones binding to a complex of the NOD classII MHC I-A g7 and epitopes derived from the islet autoantigen RegII. Libraries were generated from B-cell receptor repertoires of classII-mismatched mice immunized with RegII-pulsed NOD antigen presenting cells or from Tcell receptor repertoires in pancreatic lymph nodes of NOD mice. Both approaches yielded clones recognizing a RegIIderived epitope in the context of I-A g7 , which activated autoreactive CD4 + T-cells. A receptor with different specificity was obtained by converting the BDC2.5 TCR into single chain form. B-but not T-cells from donors vaccinated with the clones transferred protection from diabetes to NOD-SCID recipients if the specificity of the diabetes inducer cell and the single chain receptor were matched. B-cells and antibodies from donors vaccinated with the BDC2.5 single chain receptor induced a state of profound anergy in T-cells of BDC2.5 TCR transgenic NOD recipients while B-cells from donors vaccinated with a single chain receptor specific for I-A g7 RegII peptide complexes induced only partial non-responsiveness. Vaccination of normal NOD mice with receptors recognizing I-A g7 RegII peptide complexes or with the BDC2.5 single chain receptor delayed onset of T1D. Thus anti-idiotypic vaccination can be successfully applied to T1D with vaccines either generated from self-reactive T-cell clones or derived from antigen receptor libraries.
Prevalent CD8+T cell response against one peptide/MHC complex in autoimmune diabetes
Proceedings of the National Academy of Sciences of the United States of America, 1999
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 ␣ (TCR␣) rearrangement frequently expressed by CD8 ؉ T cells propagated from the earliest insulitic lesions of NOD mice (V␣17-J␣42 elements, often joined by the N-region sequence M-R-D͞E). Stimulation of splenic CD8 ؉ T cells from single-chain 8.3-TCR-transgenic NOD mice with this mimotope leads to preferential expansion of T cells bearing an endogenously derived TCR␣ chain identical to the one used by their islet-associated CD8 ؉ T cells, which is also identical to the 8.3-TCR␣ 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 peptide͞H-2K d complex. This work demonstrates that beta cell-reactive CD8 ؉ T cells mount a prevalent response against a single peptide͞MHC complex and provides one peptide ligand for CD8 ؉ T cells in autoimmune diabetes.