TCR repertoire and cytokine profiles of cerebrospinal fluid- and peripheral blood-derived T lymphocytes from patients with multiple sclerosis

CD1d-Independent Developmental Acquisition of Prompt IL-4 Gene Inducibility in Thymus CD161(NK1)−CD44lowCD4+CD8− T Cells Is Associated with Complementarity Determining Region 3-Diverse and Biased Vβ2/Vβ7/Vβ8/Vα3.2 T Cell Receptor Usage

Among Ag-inexperienced naive T cells, the CD1d-restricted NKT cell that uses invariant TCR-alpha-chain is the most widely studied cell capable of prompt IL-4 inducibility. We show in this study that thymus CD161-CD44lowCD4+CD8- T cells promptly produce IL-4 upon TCR stimulation, a response that displays biased Vbeta(2/7/8) and Valpha3.2 TCR usage. The association of Vbeta family bias and IL-4 inducibility in thymus CD161-CD44lowCD4+CD8- T cells is found for B6, B10, BALB/c, CBA, B10.A(4R), and ICR mouse strains. Despite reduced IL-4 inducibility, there is a similarly biased Vbeta(2/7/8) TCR usage by IL-4 inducibility+ spleen CD161-CD44lowCD4+CD8- T cells. Removal of alpha-galacotosylceramide/CD1d-binding cells from CD161-CD44lowCD4+CD8- thymocytes does not significantly affect their IL-4 inducibility. The development of thymus CD161-CD44lowCD4+CD8- T cells endowed with IL-4 inducibility and their associated use of Vbeta(2/7/8) are beta2-microglobulin-, CD1d-, and p59fyn-independent. Thymus CD161-CD44lowCD4+CD8- T cells produce low and no IFN-gamma inducibility in response to TCR stimulation and to IL-12 + IL-18, respectively, and they express diverse complementarity determining region 3 sequences for both TCR-alpha- and -beta-chains. Taken together, these results demonstrate the existence of a NKT cell distinct, TCR-repertoire diverse naive CD4+ T cell subset capable of prompt IL-4 inducibility. This subset has the potential to participate in immune response to a relatively large number of Ags. The more prevalent nature of this unique T cell subset in the thymus than the periphery implies roles it might play in intrathymic T cell development and may provide a framework upon which mechanisms of developmentally regulated IL-4 gene inducibility can be studied.

Multiple sclerosis retrovirus particles and recombinant envelope trigger an abnormal immune response in vitro, by inducing polyclonal Vbeta16 T-lymphocyte activation

A retroviral element (MSRV) defining a family of genetically inherited endogenous retroviruses (HERV-W) has recently been characterized in cell cultures from patients with multiple sclerosis (MS). To address the possible relationship with MS, direct detection of circulating virion RNA was proposed but revealed technically difficult to perform in standardized conditions, in the face of multiple endogenous HERV-W copies. A parallel approach has evaluated MSRV potential pathogenicity in relation to characteristic features of multiple sclerosis, in particular, T-lymphocyte-mediated immunopathology. We report here that MSRV particles induce T-lymphocyte response with a bias in the Vbeta16 chain usage in surface receptor, whatever the HLA DR of the donor. A recombinant MSRV envelope-but not core-protein reproduced similar nonconventional activation. Molecular analysis of Vbeta CDR3 showed that Vbeta16 expansions are polyclonal. Our results thus provide evidence that MSRV envelope protein can trigger an abnormal immune response with similar characteristics to that of superantigens.

Lack of restriction of T cell receptor beta variable gene usage in cerebrospinal fluid lymphocytes in acute optic neuritis

OBJECTIVES

There have been many studies reporting restricted patterns of T cell receptor usage in established multiple sclerosis and these have led to clinical trials of immunomodulation directed at deleting clonal T cell populations. The present study aims to test the hypothesis that highly restricted T cell populations are also present in the CSF in the earliest clinical stages of acute demyelinating disease of the CNS.

METHODS

T cell receptor Vbeta (TCRBV) gene expression was studied in CSF and blood in nine patients with acute optic neuritis within 7 days of onset of symptoms, six patients with an acute relapse of multiple sclerosis, and 13 control subjects. RNA was extracted and cDNA synthesised from unstimulated CSF and blood lymphocytes, and TCRBV gene segments were amplified from the cDNA by polymerase chain reaction (PCR) using 21 family specific primers. PCR products were separated by polyacrylamide gel electrophoresis and detected via a labelled oligonucleotide probe. A semiquantitative analysis of band intensity was performed by laser densitometry.

RESULTS

TCRBV mRNA was detected in the CSF of eight of nine patients with optic neuritis, six of six patients with multiple sclerosis, and five of 13 controls, and was closely correlated with the presence of oligoclonal IgG. Usage of a single TCRBV family was demonstrated in two of nine patients with optic neuritis and two of six patients with multiple sclerosis. The number of TCRBV families expressed in the other patients ranged between 5 and 15 (optic neuritis) and 4 and 17 (multiple sclerosis).

CONCLUSIONS

There is a relative lack of restriction of TCRBV usage by CSF lymphocytes in the very earliest stages (<7 days) of acute optic neuritis. This may imply either that multiple sclerosis is not a monoclonal disease even at onset, or that the autoimmune response has widened before the disease becomes clinically evident. This may have important consequences for the design of immune therapies in multiple sclerosis. Further studies are required to determine whether the CSF T cell repertoire at presentation has prognostic importance. Longitudinal studies are required to follow the CSF T cell repertoire from the time of presentation and to determine whether it may have prognostic significance.