Neuritogenic Lewis rat T cells use Tcrb chains that include a new Tcrb-V8 family member

From Immunity and Vaccines to Mammalian Regeneration

Our current understanding of major histocompatibility complex (MHC)-mediated antigen presentation in self and nonself immune recognition was derived from immunological studies of autoimmunity and virus-host interactions, respectively. The trimolecular complex of the MHC molecule, antigen, and T-cell receptor accounts for the phenomena of immunodominance and MHC degeneracy in both types of responses and constrains vaccine development. Out of such considerations, we developed a simple peptide vaccine construct that obviates immunodominance, resulting in a broadly protective T-cell response in the absence of antibody. In the course of autoimmunity studies, we identified the MRL mouse strain as a mammalian model of amphibian-like regeneration. A significant level of DNA damage in the cells from this mouse pointed to the role of the cell cycle checkpoint gene CDKN1a, or p21(cip1/waf1). The MRL mouse has highly reduced levels of this molecule, and a genetic knockout of this single gene in otherwise nonregenerating strains led to an MRL-type regenerative response, indicating that the ability to regenerate has not been lost during evolution.

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

Organ-specific autoimmune diseases and their animal models are characterized by the finding that the development of the diseases is closely associated with, or induced by, T cells reactive to organ-specific antigens. Therefore, the identification of T cell receptors (TCR) used by disease-inducing T cells within a short period of time is a key factor for designing TCR-based immunotherapy. The findings introduced in this article show that TCR associated with the development of multiple sclerosis and experimental autoimmune diseases including encephalomyelitis (EAE), neuritis (EAN) and carditis (EAC) are identifiable by complementarity-determining region 3 (CDR3) spectratyping analysis and subsequent sequencing of the CDR3 region of spectratype-derived TCR clones. It is also demonstrated that immunotherapy targeting disease-associated TCR using monoclonal antibodies and DNA vaccines significantly reduced the histological severity, and completely suppressed the inflammation in some animals. Since depletion or suppression of one of several types of effector cells does not significantly improve the severity of the disease, combined TCR-based immunotherapy should be considered as a primary therapy for T cell-mediated autoimmune diseases. TCR-based immunotherapy after rapid identification of autoimmune disease-associated TCR by CDR3 spectratyping can be applicable, not only to animal, but also to human autoimmune diseases whose pathomechanism is poorly understood.

Characterization of T cell receptor associated with the development of P2 peptide-induced autoimmune neuritis

To characterize experimental autoimmune neuritis (EAN)-inducing T cells in more detail, we performed CDR3 spectratyping analysis and found oligoclonal expansion of several Vbeta spectratypes in nerve-infiltrating T cells. Vbeta5 expansion was observed all the stages examined, whereas Vbeta8.2 and Vbeta17 expansion was mainly found at the peak and preclinical stages, respectively. Since Vbeta5 expansion persists throughout the course of the disease, Vbeta5+ T cells are judged to be the main effector cells. Vbeta8.2+ and Vbeta17+ T cells may also be pathogenic but are not the main effectors because expansion of these spectratypes was found at a limited period of time. Sequence analysis revealed that Vbeta5, Vbeta8.2 and Vbeta17 spectratype-derived TCR clones possess their own dominant sequences in the CDR3 region with no homology among the clones. These findings suggest that polyclonally activated T cells are involved in the formation of the nerve lesion. Furthermore, vaccination with Vbeta5 DNA, but not with Vbeta10 DNA, suppressed the development of EAN significantly. Collectively, these findings indicate that determination of autoimmune disease-associated TCR by CDR3 spectratyping provides useful information for designing TCR-based immunotherapy for the disease.

Depletion of Vbeta4 TCR does not induce resistance to EAN--further evidence for diversity of TCR usage

In EAN, TCR variable (V) gene usage is still controversial. A dominant usage of a TCR Vbeta4-associated idiotype has been reported. To assess the role of TCR Vbeta4 positive T-cells in susceptibility to induction of EAN, we suppressed the selection of this idiotype by neonatal treatment of Lewis rats with anti-TCR Vbeta4 monoclonal antibody (mAb). Anti-Vbeta4 treatment had no effect on development of clinical disease after immunization with the neuritogenic P2-peptide amino acids (aa) 53-78. Furthermore, lymph node cells from anti-Vbeta4 treated animals isolated after immunization with P2-peptide did not exhibit a reduced proliferative response towards whole P2-protein or P2-peptide. Our results indicate that T-cells utilizing other TCR V chains can functionally replace the neuritogenic cell population, which is dominant in stable T-cell lines.

Murine model of autoimmune hearing loss induced by myelin protein P0

Myelin protein P0 has been identified as an autoantigen in inner ear diseases. In order to study autoimmune hearing loss, we performed brain stem auditory-evoked potential (BAEP) studies on P0-sensitized mice. Two P0-sensitized mice showed hunched posture, poor coat, loss of body weight, and abnormal walking with a waddling gait. About 25% of the P0-sensitized mice developed hearing loss. In the BAEP study, peak latencies of waves I, III, and V and the interpeak latency I-III were prolonged in the P0-sensitized hearing loss group of mice. Hearing thresholds were elevated in this group of mice in comparison with the control mice. Inflammatory cell infiltration was observed in the cochlear nerve region, and a reduced number of spiral ganglion cells was also detected. These results suggest that P0-sensitized mice are a useful model for studying autoimmune inflammation of the peripheral portion of the auditory system.

T-cell receptor V beta-element expression in peripheral nerves of Lewis rats suffering from experimental autoimmune neuritis

In experimental autoimmune neuritis (EAN), peripheral nerves are infiltrated by T-lymphocytes and macrophages. By RT-PCR and sequence analysis we characterized TCR V beta-element usage in sciatic nerve tissue of Lewis rats suffering from EAN induced by immunization with peripheral myelin antigens. Several TCR V beta-chain sequences were detected, which did not show homology to sequences of P2-reactive T cells published so far. In EAN induced with peripheral nerve myelin, but not with P2-protein or P2 peptide aa 53-78, TCR V beta 8.2 sequences identical to sequences of encephalitogenic myelin basic protein (MBP) reactive T-cells were identified. These results provide further evidence for a contribution of MBP-directed T-cell reactivity to the pathogenesis of myelin induced EAN and may have implications for the pathogenesis of human demyelinating neuropathies.

Regulatory T cells specific for the same framework 3 region of the Vbeta8.2 chain are involved in the control of collagen II-induced arthritis and experimental autoimmune encephalomyelitis

Recent evidence indicates that chronic autoimmune disease can result from breakdown of regulation and subsequent activation of self-reactive T cells. In many murine autoimmune disease systems and in the Lewis rat, antigen-specific T cells utilizing the T cell receptor (TCR) Vbeta8.2 gene segment play a major role. In the myelin basic protein-induced experimental autoimmune encephalomyelitis (EAE) model in H-2(u) mice, we had shown that T cells recognizing a peptide determinant within the framework 3 region of the Vbeta8.2 chain have a critical role in influencing the course of the disease. Here, we report experiments in another disease system, collagen II (CII)-induced arthritis (CIA) in DBA/1LacJ (H-2(q)) mice, indicating a remarkably parallel control circuit to that found for EAE. A critical role is played by CII-specific Vbeta8.2-bearing T cells in the CIA system, which we have confirmed. Animals treated with the superantigen SEB before CII administration are significantly protected from CIA. Next, we tested the ability of peptides encompassing the entire Vbeta8.2 chain to induce proliferative responses. Only TCR peptide B5 (amino acids 76-101), a regulatory peptide in EAE, induced proliferation. B5 was then used to vaccinate DBA/1LacJ mice and was shown to reduce greatly the severity and incidence of CIA as measured by joint inflammation or histology. Furthermore, similar protection was found when B5 was administered after CII immunization. It was shown that there is physiological induction of a proliferative response to B5 during CIA and that the determinant within B5 is produced from a single chain TCR construct containing the entire Vbeta8.2 chain. Finally, the regulation of CIA is discussed in the context of other experimental autoimmune diseases, especially EAE, with emphasis on what appear to be strikingly common mechanisms.

Protection against generalized autoimmunity of the nervous system (GANS), a novel animal model with combined features of EAE, EAN and EAU by a recombinant HIV-1 Tat37-72 peptide-based multiple T cell epitope vaccine

A new model of multi-compartment auto-immune disease has been established to analyze the effects of polyvalent recombinant peptide vaccines. A synthetic gene encoding major pathogenic determinants for Lewis rats of guinea pig myelin basic protein (MBP68-84), bovine interphotoreceptor retinoid binding protein (IRBP1169-1191), and bovine P2 protein (P2,53-78) was used to induce Generalized Autoimmunity of the Nervous System (GANS), which is characterized by development of auto-immune infiltration of the brain and spinal cord, the eyes, the pineal organ and the peripheral nerves. Thus, this model integrates the prominent features of three auto-immune diseases: experimental autoimmune encephalomyelitis (EAE), neuritis (EAN) and uveitis (EAU). In this study, GANS was used to study the effect of HIV-1 Tat37-72 targeting peptide on vaccination by recombinant polyvalent T cell auto-antigen vaccine. Depending on the route of administration, the recombinant vaccine effectively protects against the development of auto-immune nervous system inflammation.

T cell receptor V beta gene usage in Guillain-Barré syndrome

We set out to determine whether the T cell receptor (TCR) V beta gene usage in acute inflammatory demyelinating polyradiculoneuropathy (AIDP) is restricted. We separated activated from non-activated peripheral blood T cells with anti-IL2 receptor (anti-CD25) antibody-labelled magnetic beads from four AIDP patients and four normal control (NC) subjects. The TCR V beta gene usage of circulating activated and non-activated T cells was heterogeneous in all the patients and controls, but the activated T cells of all four of the AIDP patients showed a more limited usage of V beta genes and enhanced V beta 15 usage, as compared to the non-activated T cells. This was not seen in the healthy controls. The activated and non-activated T cells from a patient with acute motor and sensory axonal neuropathy (AMSAN) showed a similar V beta gene usage to that of the controls. From a further patient with AIDP, we studied the V beta gene usage of short-term T cell lines reactive to the peripheral nerve myelin proteins P2, P0 and the P0 peptide amino acid sequence 194-208. The V beta gene usage of the lines was heterogeneous, with enhanced usage of V beta 15 in the cell line responsive to the Pzero peptide. We conclude that T cells activated during the immune response associated with AIDP preferentially used V beta 15, which may indicate a restricted response to a common antigen, or a role for an as yet undefined superantigen in the pathogenesis of AIDP.

Generalized autoimmunity of the nervous system (GANS) induced by a recombinant protein composed of major pathogenic determinants of MBP, IRBP, and P2 protein: suppression of inflammation by a monoclonal antibody against activated rat T line cells

We have developed a new model of generalized autoimmunity of the rat nervous system to study differential immunoregulation, barrier-function, and parenchymal inflammatory processes. We designed a multicomponent synthetic gene encoding major pathogenic determinants for Lewis rats of myelin basic protein (MBP), interphotoreceptor retinoid binding protein (IRBP), and P2 protein. Immunization with the recombinant protein induces a monophasic disease with inflammatory lesions in the eye, brain, spinal cord, and peripheral nerves. Rats recovered from GANS were tolerant against the induction of experimental autoimmune encephalomyelitis (EAE), neuritis (EAN), and uveoretinitis (EAU) by immunization with synthetic autoantigen-peptides/CFA. To demonstrate an application of GANS we have used a monoclonal antibody raised against encephalitogenic rat T lymphocytes. We show that this monoclonal antibody is suppressing not only inflammatory cell infiltration of brain and spinal cord, but as well of the eyes and the peripheral nervous system.