Characterization of T cell receptor (TCR) of organ-specific autoimmune disease-inducing T cells and TCR-based immunotherapy with DNA vaccines

Detection of clonal T-cell-receptor (TCR) Vbeta rearrangements in explanted dilated cardiomyopathy hearts by semi-nested PCR, GeneScan, and direct sequencing

Background

Viral infection and anti-cardiac immunity are involved in the pathogenesis of dilated cardiomyopathy (DCM). Immunity targeting particular antigens may evoke expansion of reactive T-cell clones.

Material/Methods

Myocardial tissues from explanted hearts were investigated for clonal T-cell-receptor- (TCR-) β rearrangements by an established semi-nested polymerase chain reaction (PCR), followed by high-resolution GeneScan analysis and direct sequencing. From 17 explanted DCM hearts, 3 myocardial samples each were obtained from the right ventricle, the septum, and the left ventricle (total: 9 myocardial samples per case). Six explanted hearts with non-DCM cardiomyopathy entities served as controls.

Results

GeneScan analysis revealed polyclonal TCR-β rearrangements in all controls. In contrast, at least 1 myocardial sample in 9 out of 17 DCM hearts (total: 20 of the 81 DCM specimens) displayed single dominant TCR-β PCR products consistent with the presence of clonal T-cell populations. Direct sequencing of the clonal TCR-β PCR-products disclosed an involvement of Vb 19.01 segments in 14 of the dominant amplificates (70%). Further TCR-Vβ segments involved in clonal TCR-β rearrangements of DCM hearts were Vβ 6-1.01 (n=1), Vβ 6-3.01 (n=2), Vβ 6-5.01 (n=1), Vβ 10-3.02 (n=1), and Vβ 19.03 (n=1).

Conclusions

The detectability of clonal TCR-β rearrangements indicates a pathogenic relevance of this finding in DCM. The predominance of Vβ 19.01 segments suggests that the immune response in DCM patients targets particular epitopes. However, the partly heterogenic TCR-β populations in various myocardial samples from the respective cases support the notion that T-cell immunity may target multiple epitopes in human DCM.

Spectratype analysis of clonal T cell expansion in murine experimental stroke

T lymphocytes are major contributors to post-ischemic neuroinflammation following ischemic stroke. However, the mode of postischemic T cell activation remains a controversial issue. Therefore, this study aimed to directly investigate antigen-dependent clonal T cell expansion after experimental brain ischemia using spectratype/immunoscope analysis. We detected clonal T cell expansion in ischemic brains and to a lesser extent in secondary lymphatic organs and characterized its time course. This is the first study presenting direct evidence of clonal T cell expansion after stroke - however, with delayed kinetics that make antigen-dependent mechanisms unlikely in acute post-ischemic neuroinflammation.

Neuropathogenesis of Theiler's murine encephalomyelitis virus infection, an animal model for multiple sclerosis

Theiler's murine encephalomyelitis virus (TMEV) infection of mice is an experimental model for multiple sclerosis (MS). TMEV induces a biphasic disease in susceptible mouse strains. During the acute phase, 1 week after infection, TMEV causes polioencephalomyelitis characterized by infection and apoptosis of neurons in the gray matter of the brain. During the chronic phase, about 1 month after infection, virus infects glial cells and macrophages, and induces inflammatory demyelination with oligodendrocyte apoptosis and axonal degeneration in the white matter of the spinal cord. Although antibody, CD4(+), and CD8(+) T cell responses against TMEV capsid proteins play important roles in neuropathogenesis, infectious virus with persistence is necessary to induce demyelination; in general, adoptive transfer of antibody or T cells alone did not induce central nervous system (CNS) disease. The TMEV model can be useful for testing new therapeutic strategies specifically as a viral model for MS. Therapies targeting adhesion molecules, axonal degeneration, and immunosuppression can be beneficial for pure autoimmune CNS demyelinating diseases, such as experimental autoimmune encephalomyelitis, but could be detrimental in virus-induced demyelinating diseases, such as progressive multifocal leukoencephalopathy.

Collagen-specific T-cell repertoire in blood and synovial fluid varies with disease activity in early rheumatoid arthritis

Introduction

Type II collagen is a DR4/DR1 restricted target of self-reactive T cells that sustain rheumatoid arthritis. The aim of the present study was to analyze the T-cell receptor repertoire at the onset of and at different phases in rheumatoid arthritis.

Methods

We used the CDR3 BV-BJ spectratyping to study the response to human collagen peptide 261–273 in 12 patients with DR4⁺ rheumatoid arthritis (six at the onset of disease and six during the course of disease) and in five healthy DR4⁺ relatives.

Results

The collagen-specific T-cell repertoire is quite restricted at the onset of disease, involving approximately 10 rearrangements. Within the studied collagen-specific rearrangements, nearly 75% is shared among patients. Although the size of the repertoire used by control individuals is comparable to that of patients, it is characterized by different T-cell receptors. Part of the antigen-specific T-cell repertoire is spontaneously enriched in synovial fluid. The specific T-cell repertoire in the periphery was modulated by therapy and decreased with the remission of the disease. Failure of immunoscopy to detect this repertoire was not due to suppression of collagen-driven proliferation in vitro by CD4⁺ CD25⁺ T cells. Clinical relapse of the disease was associated with the appearance of the original collagen-specific T cells.

Conclusions

The collagen-specific T-cell receptor repertoire in peripheral blood and synovial fluid is restricted to a limited number of rearrangements in rheumatoid arthritis. The majority of the repertoire is shared between patients with early rheumatoid arthritis and it is modulated by therapy.

Characterization of T-cell population in children with prolonged fetal exposure to dexamethasone for anti-Ro/SS-A antibodies associated congenital heart block

The objectives of the study were to characterize the production, function and survival of T lymphocytes of children with prolonged fetal exposure to dexamethasone for anti-Ro/SS-A antibodies associated congenital complete heart block. The analysis of thymic function, studied by measuring the level of T-cell receptor excision circles, was performed by real time PCR, the composition of T-cell subpopulation was evaluated by flow cytometry and the T-cell diversity was assayed by heteroduplex analysis. T-cell competence was gauged at two functional levels by determining the proliferation and the number of T-cell divisions and by measuring gamma-interferon production after mitogenic stimulation. We observed that the thymic output, distribution of T-cell subsets, thymidine incorporation, number of T-cell divisions, and y-interferon production were comparable to those of age-matched control. On the contrary, heteroduplex analysis demonstrated the presence of both polyclonal and oligoclonal peripheral T-cell repertoires. In conclusion, the analysis of the T-cell compartment in children with prolonged intrauterine exposure to high dose dexamethasone did not disclose any relevant abnormality, except a restriction of T-cell receptor diversity in some patients.

Characterization of the T cell receptor repertoire in the Japanese neuromyelitis optica: T cell activity is up-regulated compared to multiple sclerosis

To characterize T cell immunity in Japanese neuromyelitis optica (NMO), we examined the T cell receptor (TCR) repertoire in NMO patients with complementarity-determining region 3 (CDR3) spectratyping and compared the results with those from multiple sclerosis (MS) patients and healthy subjects. Both NMO and MS patients had a larger number of clonally expanded Vbeta genes than healthy subjects. Moreover, NMO patients had a significantly larger number of expanded Vbetas than MS patients. The detailed analysis revealed that Vbeta1 and Vbeta13 were significantly activated in NMO than MS. These results reflected unique pathophysiology of Japanese NMO, which is distinguishable from that of MS. Furthermore, longitudinal examinations of the TCR repertoire demonstrated that the number of clonally expanded Vbetas in NMO correlates with the Kurtzke Expanded disability status scale (EDSS). Although the activation pattern of the TCR repertoire in relapsing-remitting MS (RRMS) was similar to that in NMO, secondary progressive MS (SPMS) patients with longer disease durations and higher EDSS scores consistently had a smaller number of clonally expanded Vbetas than RRMS patients. Detailed TCR investigations will provide useful information to evaluate the clinical and immunological status of NMO and MS and to develop effective immunotherapies.

Nonviral Abeta DNA vaccine therapy against Alzheimer's disease: long-term effects and safety

It was recently demonstrated that amyloid beta (Abeta) peptide vaccination was effective in reducing the Abeta burden in Alzheimer model mice. However, the clinical trial was halted because of the development of meningoencephalitis in some patients. To overcome this problem, anti-Abeta antibody therapy and other types of vaccination are now in trial. In this study, we have developed safe and effective nonviral Abeta DNA vaccines against Alzheimer's disease. We administered these vaccines to model (APP23) mice and evaluated Abeta burden reduction. Prophylactic treatments started before Abeta deposition reduced Abeta burden to 15.5% and 38.5% of that found in untreated mice at 7 and 18 months of age, respectively. Therapeutic treatment started after Abeta deposition reduced Abeta burden to approximately 50% at the age of 18 months. Importantly, this therapy induced neither neuroinflammation nor T cell responses to Abeta peptide in both APP23 and wild-type B6 mice, even after long-term vaccination. Although it is reported that other anti-Abeta therapies have pharmacological and/or technical difficulties, nonviral DNA vaccines are highly secure and easily controllable and are promising for the treatment of Alzheimer's disease.

Recombinant idiotypic TCRβ chain immunization in mice generates antigen specific T cell response

Vaccination remains the most cost-effective means of preventing infectious diseases. Success of vaccination depends on generation of effective memory response. Understanding the mechanism of generation and maintenance of immunological memory would help in the design of rational vaccines. T lymphocytes play a central role in the generation of protective immune response against many microbial infections. A hypothesis known as relay hypothesis was earlier proposed, which explains the maintenance of immunological memory through interaction of idiotypic and anti-idiotypic lymphocytes. In the present study, we have shown that immunization with a model antigen, chicken ovalbumin specific T cell receptor beta chain (idiotypic TCR) generates TCR specific antibody and anti-idiotypic T cell responses as well as ovalbumin specific T cell response. We further show that boosting of ovalbumin primed mice with ovalbumin specific idiotypic TCRbeta DNA or TCRbeta protein gives memory response for ovalbumin. This study provides experimental evidence for perpetuation of immunological memory through idiotypic network interactions.

DNA Vaccination Against Specific Pathogenic TCRs Reduces Proteinuria in Active Heymann Nephritis by Inducing Specific Autoantibodies

We have previously identified potential pathogenic T cells within glomeruli that use TCR encoding Vbeta5, Vbeta7, and Vbeta13 in combination with Jbeta2.6 in Heymann nephritis (HN), a rat autoimmune disease model of human membranous nephritis. Vaccination of Lewis rats with naked DNA encoding these pathogenic TCRs significantly protected against HN. Proteinuria was reduced at 6, 8, 10, and 12 wk after immunization with Fx1A (p < 0.001). Glomerular infiltrates of macrophages and CD8(+) T cells (p < 0.005) and glomerular IFN-gamma mRNA expression (p < 0.01) were also significantly decreased. DNA vaccination (DV) causes a loss of clonality of T cells in the HN glomeruli. T lymphocytes with surface binding of Abs were found in DNA vaccinated rats. These CD3(+)/IgG(+) T cells expressed Vbeta5 and Vbeta13 that the DV encoded. Furthermore, FACS shows that these CD3(+)/IgG(+) cells were CD8(+) T cells. Analysis of cytokine mRNA expression showed that IL-10 and IFN-gamma mRNA were not detected in these CD3(+)/IgG(+) T cells. These results suggest that TCR DNA vaccination produces specific autoantibodies bound to the TCRs encoded by the vaccine, resulting in blocking activation of the specific T cells. In this study, we have shown that treatment with TCR-based DV, targeting previously identified pathogenic Vbeta families, protects against HN, and that the mechanism may involve the production of specific anti-TCR Abs.

CDR3 spectratyping analysis of the T cell receptor repertoire in Guillain-Barré and Fisher syndromes

Several autoimmune and infectious disorders show oligoclonal expansion of particular T cell phenotypes. The extent of T cell involvement in the pathogenesis of Guillain-Barré syndrome (GBS), a post-infectious autoimmune neuropathy, however, is not clear. To identify the pathogenic T cell phenotypes in GBS and Fisher syndrome (FS), variations in T cell receptor use of the V beta 1-24 and V delta 1-5 chain genes were analyzed at complementarity-determining region 3 level in 119 patients with GBS or FS. Overall, V beta and V delta spectratypes were expanded more frequently in patients with GBS (V beta in 77%, V delta in 53%) or FS (V beta in 75%, V delta in 65%) than in the healthy controls (V beta in 59%, V delta in 38%). No particular spectratype was significantly associated with GBS or FS. Subgrouping the patients by Campylobacter jejuni serology and anti-ganglioside IgG antibodies also failed to detect particular spectratype gene use. The frequency of V beta 5.2 expansion tended to be higher in patients with positive Haemophilus influenzae serology (50%) than in the controls (7%), but the difference was not significant. Our findings show that oligoclonal expansion of T cells bearing particular type T cell receptor V beta and V delta genes frequently occurs in GBS and FS, suggestive that T cells mediate the development of these neuropathies. The predominant phenotypes vary, even within subgroups of patients with a syndrome of single etiological origin or those with uniform serological features.

Increased expression of phospholipase D1 in the sciatic nerve of rats with experimental autoimmune neuritis

Phospholipase D1 (PLD1) expression in the sciatic nerve was studied in induced experimental autoimmune neuritis (EAN) in Lewis rats. PLD1 immunoreactivity was seen in some Schwann cells in the sciatic nerves of normal rats. In parallel with the progression of EAN, PLD1-positive Schwann cells significantly increased in number and showed intense immunoreactivity. PLD1 was also detected in some ED1+ macrophages in EAN lesions. These results suggest that PLD1 in macrophages and Schwann cells plays an important role in the activation of these cells in the pathogenesis of EAN, an animal model of human peripheral demyelinating disease.

Characterization of T cell hybridomas raised against a glycopeptide containing the tumor-associated T antigen, (betaGal (1-3) alphaGalNAc-O/Ser)

T cell hybridomas were raised against the glycopeptide S(72) (Core-1) containing the tumor-associated disaccharide betaGal (1-3) alphaGalNAc (Core-1) O-linked to serine at position 72 in the mouse hemoglobin derived decapeptide Hb (67-76). All hybridomas recognized the glycopeptide S(72) (Core-1). Two of the selected hybridomas responded, however, much better to the S(72) (Tn) glycopeptide containing the monosaccharide alphaGalNAc O-linked to serine. In addition, one hybridoma cross-responded to the glycopeptide T(72) (Core-1) having a threonine at position 72 instead of a serine. No cross-responses were found to other glycopeptides consisting of the same hemoglobin peptide with different glycans attached or to the unglycosylated peptides. The T cell receptor Valpha and Vbeta usage was clearly diverse. The CDR3alpha regions demonstrated moreover a predominance of small polar amino acid side chains, and three hybridomas contained a common sequence motif. All the sequenced CDR3beta regions contained furthermore a conserved proline-glycine motif. In conclusion, immunization with the disaccharide containing glycopeptides S(72) (Core-1) created a heterogeneous population of glycopeptide specific T cells with the ability of cross-responding toward related glycopeptides.

Characterization of T cells that are activated after depletion of major encephalitogenic T cells in rat autoimmune encephalomyelitis

In rat experimental autoimmune encephalomyelitis (EAE), encephalitogenic T cells mainly use Vbeta8.2 of TCR, but it is not clear whether Vbeta8.2 is the sole encephalitogenic TCR. To address this issue, we examined the immunological status of Lewis rats that had been treated with anti-Vbeta8.2 mAb and immunized with myelin basic protein (MBP). It was demonstrated that rats in which the majority of Vbeta8.2+ T cells had been depleted developed clinical EAE and possessed newly expanded Vbeta10. Analysis of T cell lines established from these animals revealed that T line cells responded to a minor epitope in the MBP molecule. However, treatment with a mixture of anti-Vbeta8.2 and anti-Vbeta10 mAbs reduced the clinical severity of EAE but did not induce complete suppression of the disease due to new activation of Vbeta6. These findings suggest that rapid and frequent examination of the TCR repertoire is essential to identify pathogenic TCRs and to establish TCR-based immunotherapy for autoimmune diseases.