Antigen therapy of experimental autoimmune encephalomyelitis selectively induces apoptosis of pathogenic T cells

doi:10.1016/j.jneuroim.2006.11.031

Journal of Neuroimmunology

Volume 183, Issues 1–2, February 2007, Pages 146-150

https://doi.org/10.1016/j.jneuroim.2006.11.031 Get rights and content

Abstract

Administration of high-dose myelin antigen induces massive T cell apoptosis in experimental autoimmune encephalomyelitis (EAE) but the nature of the target cells remains elusive. Here we have used a cell line established in eGFP-transgenic Lewis rats to distinguish between pathogenic and bystander T cells in adoptive transfer EAE. Intravenous application of gpMBP strongly reduced the amount of encephalitogenic cells in spinal cord and spleen while the number of the other T cells remained constant. This could be attributed to their differential sensitivity to apoptosis. Thus, antigen therapy selectively targets pathogenic T cells and should therefore limit potential adverse effects.

Introduction

Experimental autoimmune encephalomyelitis (EAE) is a T cell-mediated inflammatory disease of the CNS that is widely used as a model for multiple sclerosis (MS) (Gold et al., 2006). In the Lewis rat, EAE follows a monophasic disease course and can be induced by adoptive transfer of encephalitogenic T cells (AT-EAE) (Ben-Nun et al., 1981, Swanborg, 2001). The inflammatory cascade is initiated by autoreactive T lymphocytes that cross the blood brain barrier and start to secrete pro-inflammatory cytokines and chemokines. Subsequently, additional autoreactive T cells are recruited to the CNS, which then leads to an amplification of the immune response (Flügel et al., 2001). Finally, bystander T cells, macrophages and granulocytes are recruited from the recipient's lymphoid organs to the inflammatory lesion, which results in demyelination (Gold et al., 2006).

Interferon-β (IFN-β) and Glatiramer Acetate (GA) are the most commonly used drugs to treat relapsing–remitting multiple sclerosis (Murray, 2006). While IFN-β induces a rather complex immunomodulation, GA has been developed as an example of immunotherapy based on the application of a putative myelin autoantigen (Arnon and Sela, 2003). Furthermore, antigen administration in rodents was used to treat experimental autoimmune disorders of the nervous system (Critchfield et al., 1994, Weishaupt et al., 1997, Weishaupt et al., 2000). In this case, intravenous injection of high-dose gpMBP results in the induction of T cell apoptosis, leading to an amelioration of the disease course. However, it remains elusive whether cell death occurs in all types of T cells or whether the effect is restricted to the pathogenic T effector cells. This question can be addressed using an encephalitogenic T cell line recently established from eGFP-transgenic Lewis rats (Tischner et al., 2006, van den Brandt et al., 2004). Using an AT-EAE model we now show that the pathogenic T effector cells are preferentially eliminated by apoptosis after high-dose antigen therapy, while the bystander T cells in the spinal cord and normal T cells in the secondary lymphoid organs are only marginally affected.

Section snippets

Induction of EAE

AT-EAE was induced in 6-week old female Lewis rats (Charles River, Sulzfeld, Germany) by i.v. injection of 8 × 10⁶ freshly activated eGFP⁺ MBP-specific T cells as previously described (Tischner et al., 2006). The T cell line used in this experiment is comprised of more than 95% CD4⁺ TCRβ⁺ cells and underwent five restimulation cycles with gpMBP. Around 30% of the cells are Vβ8.2⁺ whereas 13% express the Vβ3.3 restriction element (unpublished data). Animals were inspected daily and the severity of

Results

It was previously shown that repetitive high-dose antigen therapy ameliorates AT-EAE in Lewis rats due to the induction of T cell apoptosis (Weishaupt et al., 2000). To assess the mechanism at work, animals were treated i.v. with high-dose gpMBP for only 1 day after the first disease symptoms had been established. Using this protocol, we observed a significant reduction in the number of T cells in the spinal cord as compared to controls, both by flow cytometry and immunohistochemistry (Fig. 1A,C

Discussion

The attractiveness of antigen therapy in the treatment of MS stems from its supposed selectiveness for pathogenic T cells. However, it had not yet been demonstrated that high-dose antigen therapy indeed selectively targets the encephalitogenic T cells while sparing other T cells. In a previous study in Lewis rats it had been shown that antigen therapy increased apoptosis in the CNS among T cells expressing the TCR Vβ8.2 variant, which is used by around 30% of all encephalitogenic MBP-specific T

Acknowledgements

We thank Sabrina Kirch and Christian Bauer for expert technical help. This work was supported by grants from the Interdisziplinäres Zentrum für Klinische Forschung (IZKF A-44).

References (18)

A. Flügel et al.
Migratory activity and functional changes of green fluorescent effector cells before and during experimental autoimmune encephalomyelitis
Immunity
(2001)
R. Gold et al.
T-cell apoptosis in autoimmune diseases: termination of inflammation in the nervous system and other sites with specialized immune-defense mechanisms
Trends Neurosci.
(1997)
A. Weishaupt et al.
Schwann cell apoptosis in experimental autoimmune neuritis of the Lewis rat and the functional role of tumor necrosis factor-alpha
Neurosci. Lett.
(2001)
R. Arnon et al.
Immunomodulation by the copolymer glatiramer acetate
J. Mol. Recognit.
(2003)
A. Ben-Nun et al.
The rapid isolation of clonable antigen-specific T lymphocyte lines capable of mediating autoimmune encephalomyelitis
Eur. J. Immunol.
(1981)
A. Chan et al.
Usage of Vbeta3.3 T-cell receptor by myelin basic protein-specific encephalitogenic T-cell lines in the Lewis rat
J. Neurosci. Res.
(1999)
J.M. Critchfield et al.
T cell deletion in high antigen dose therapy of autoimmune encephalomyelitis
Science
(1994)
P. Fontoura et al.
Emerging therapeutic targets in multiple sclerosis
Curr. Opin. Neurol.
(2006)
R. Gold et al.
Understanding pathogenesis and therapy of multiple sclerosis via animal models: 70 years of merits and culprits in experimental autoimmune encephalomyelitis research
Brain
(2006)

There are more references available in the full text version of this article.

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Short communicationAntigen therapy of experimental autoimmune encephalomyelitis selectively induces apoptosis of pathogenic T cells

Abstract

Introduction

Section snippets

Induction of EAE

Results

Discussion

Acknowledgements

Immunity

Trends Neurosci.

Neurosci. Lett.

Immunomodulation by the copolymer glatiramer acetate

J. Mol. Recognit.

The rapid isolation of clonable antigen-specific T lymphocyte lines capable of mediating autoimmune encephalomyelitis

Eur. J. Immunol.

Usage of Vbeta3.3 T-cell receptor by myelin basic protein-specific encephalitogenic T-cell lines in the Lewis rat

J. Neurosci. Res.

T cell deletion in high antigen dose therapy of autoimmune encephalomyelitis

Science

Emerging therapeutic targets in multiple sclerosis

Curr. Opin. Neurol.

Understanding pathogenesis and therapy of multiple sclerosis via animal models: 70 years of merits and culprits in experimental autoimmune encephalomyelitis research

Brain

Short communication
Antigen therapy of experimental autoimmune encephalomyelitis selectively induces apoptosis of pathogenic T cells