Generation and analysis of T cell receptor transgenic rats to model CNS autoimmunity

by Alexandra Kitz
Doctoral thesis
Date of Examination:2013-10-29
Date of issue:2014-01-27
Advisor:Prof. Dr. Alexander Flügel
Referee:Prof. Dr. Wolfgang Brück
Referee:Prof. Dr. Dr. Detlev Schild
Referee:Prof. Dr. Dr. Hannelore Ehrenreich
Persistent Address: http://dx.doi.org/10.53846/goediss-4330

 

 

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Abstract

English

Autoreactive T cells directed against CNS antigens seem to play an essential role at least in the initiation of multiple sclerosis. To improve our understanding about the function of pathogenic T cells in CNS autoimmunity we aimed to endow the classical neuroimmunlogical Lewis rat EAE model with new analytic power. To do this, we generated two TCR transgenic Lewis strains: the rMT-II strain carrying T cells specific for the self-antigen myelin basic protein and the rOT-II strain in which the transgenic TCR is specific for chicken ovalbumin. To our knowledge, these are first available TCRtg models created in R. norvegicus. The immune system of the rMT-II+/+ strain is characterised by a high proportion of CD4+ MHC class II restricted T cells readily responding to MBP challenge by proliferating and producing proinflammatory cytokines. Although no spontaneous EAE was observed in rMT-II rats, this strain is highly susceptible to an early-onset severe monophasic EAE induced by active immunization even with reduced amounts of adjuvant or antigen. Repeated immunization induced relapse EAE in rMT-II, but not in WT Lewis rats. Peripheral T cells isolated from rMT-II donors were able to mediate an accelerated onset of active EAE upon transfer into WT recipients. Remarkably, the effector T cell lines established from rMT-II rats were highly encephalitogenic and caused severe EAE including atypical symptoms with increased propensity to infiltrate not only the spinal cord but also brain tissue. In the rOT-II+/+ strain the majority of peripheral T cells express a transgenic TCR specific for ovalbumin. In this strain, however, thymic development is disturbed leading to moderate lymphopenia, aberrant expression of the CD8 coreceptor in mature OVA-reactive T cells and reduction of the CD62L+ population. Still, this line can be used to track priming and migration of non-pathogenic OVA-specific T cells upon adoptive transfer. A green fluorescent marker which is co-expressed with each transgenic TCR greatly facilitates phenotyping and analysis of T cell migration. Further, its high expression by endothelial and myeloid cells can be exploited to visualize interaction of meningeal BBB structures with invading immune cells by TPM using rOT-II animals as a host for transfer experiments. Using an experimental setup comprising adoptive transfer and local activation in the draining LN, we performed analysis of migration and gene expression of cytokines and chemokine receptors in naïve and effector populations of MBP- and OVA-specific T cells in vivo. Furthermore, TPM analysis of rMT-II+/+ cells invading the spinal cord during EAE induced by peripheral T cell activation revealed differences in behaviour of primary versus effector T cell subtypes.
Keywords: Lewis rat; TCR transgenic; MBP; EAE
 
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