T cell receptor V beta usage in rheumatoid nodules: marked oligoclonality among IL-2 expanded lymphocytes

Pathogenic mechanisms in the rheumatoid nodule: comparison of proinflammatory cytokine production and cell adhesion molecule expression in rheumatoid nodules and synovial membranes from the same patient

OBJECTIVE

To investigate the production of proinflammatory cytokines and expression of cell adhesion molecules in the rheumatoid nodule.

METHODS

Cytokine content (tumor necrosis factor alpha [TNFalpha], interleukin-1beta [IL-1beta], and IL-1 receptor antagonist [IL-1Ra]), at the messenger RNA (mRNA) and protein levels, and cell adhesion molecule expression were studied in 16 rheumatoid nodules and 6 synovial membranes.

RESULTS

Macrophages in the rheumatoid nodules contained TNFalpha, IL-1beta, and IL-1Ra mRNA and protein, particularly in perivascular cells of the stroma and in the palisading layer. All cell adhesion molecules studied were expressed in both the rheumatoid nodules and synovial membranes, with increased expression of E-selectin in the rheumatoid nodule compared with the synovial membrane, and with the absence of vascular cell adhesion molecule 1 expression on cells of the palisading layer in the rheumatoid nodule.

CONCLUSION

The presence of similar proinflammatory cytokines and cell adhesion molecules in the rheumatoid nodule and synovial membrane suggests that similar pathogenic processes result in the chronic inflammation and tissue destruction in these lesions.

A comparative phenotypical analysis of rheumatoid nodules and rheumatoid synovium with special reference to adhesion molecules and activation markers

OBJECTIVES

(1) To analyse the in situ expression of adhesion molecules in rheumatoid nodules. (2) To compare the endothelial expression of adhesion molecules in synovial tissue and subcutaneous nodules obtained from the same patients. (3) To compare the expression of adhesion molecules and activation markers on T cell lines from nodules and synovium.

METHODS

(1) Immunohistochemical analysis by APAAP technique of E selectin, CD44, ICAM-1, PECAM-1, and VCAM-1 was performed on 10 rheumatoid nodules from seven patients with rheumatoid arthritis (RA); nodules and synovium were simultaneously analysed from three patients. (2) T cell lines were generated from RA nodules (n = 7) and synovium (n = 7) by interleukin 2 expansion, and subsequently characterised by flow cytometry for surface expression of alpha E beta 7, alpha 4 beta 7, CD44, L selectin, LFA-1a, PECAM-1, and CD30.

RESULTS

(1) In rheumatoid nodules, the palisading layer strongly stains for ICAM-1 and PECAM-1, but less pronounced for CD44. VCAM-1 staining was usually negative. ICAM-1 is upregulated in the vessels surrounding the central zone of fibrinoid necrosis. The immunohistological picture in different nodules derived from the same patient was similar. (2) The endothelial expression of adhesion molecules is comparable in RA nodules and synovium on an individual level, except for E selectin, which is overexpressed in nodule endothelium. (3) T cell lines from nodules and synovium display similar adhesion molecule profiles. However, the expression of CD30, a T cell activation marker linked with Th2 subsets, is higher in nodules compared with synovium.

CONCLUSION

These data support a recirculation hypothesis of T cells between articular and extra-articular manifestations in RA, although the activation state of the T cells in each of these localisations may differ.

Generation and functional characterization of anti-clonotype antibodies to human T-cell receptors

Monoclonal antibodies (mAb) directed against the clonotypic structure of the T-cell receptor (TCR) may be useful reagents in the study and therapy of T-cell-mediated diseases. In contrast to several reports concerning the generation of anti-clonotype mAb to mouse TCR, only very limited numbers of anti-clonotype mAb to human TCR have been described. So far, a suitable method for the generation of anti-clonotype mAb to a given TCR has not been available and in this report we describe a novel strategy for the generation of such mAb. Mice were immunized with intact human T-cells. Then. spleen cell populations were precleared from B-cells reactive to CD3 and the constant region of the TCR by adsorption to TCR/CD3 complexes derived from an irrelevant T-cell clone. Subsequently, clonotype-specific B-cells were selected with TCR/CD3 complexes from the T-cell clone of interest. The small number of B-cells resulting from this selection were clonally expanded in a B-cell culture system and then immortalized by mini-electrofusion. Ten clonotype-specific mAb were generated against a DRB1*0401-restricted T-cell clone recognizing an epitope of the human cartilage glycoprotein 39 (HC gp-39). All mAb immunoprecipitated a heterodimeric 85 kDa protein. Absolute specificity was demonstrated in a T-cell agglutination test with the T-cell clone of interest compared to a set of 16 defined, irrelevant T-cell clones or lines. In functional assays, the mAb were found to inhibit or block antigen-specific T-cell stimulation. In addition, crosslinked mAb were found to stimulate proliferation of the specific clone in the absence of antigen and antigen presenting cells (APC). Such mAb may have clinical relevance in deleting or modulating autoreactive T-cells in a clonotype-specific manner.

The role of T cells in rheumatoid arthritis

The most striking arguments in favor of a T cell dependent nature of RA are the strong association of the disease with selected class II HLA haplotypes (the "shared epitope" hypothesis) and the fact that, in experimental animal models such as adjuvant arthritis, the disease can be transferred by isolated T cell lines. It is true that T cell activation at the site of inflammation is not excessive. However, there is now unequivocal evidence for focal synthesis of IL-2 and IFN-gamma in the RA synovial membrane and one may realise that a limited but specific T cell activation may be sufficient to induce or perpetuate the immune process. This same argument may explain the lack of clear TCR restriction at the sites of inflammation. Until now, no antigen has been demonstrated to initiate and/or perpetuate RA. Different antigens though have been incriminated in the pathogenesis of RA, including cartilage antigens (collagen, proteoglycans, chondrocyte antigens), heat shock proteins or exogenous (viral/bacterial) antigens. Unless one can pick up the right antigen and clone the relevant T cells, it will be very hard to directly prove a T cell-dependent nature of the disease.

T cell receptor usage in autoimmune disease

Activated T-cells are believed to play a critical role in the pathogenesis of autoimmune disease. In experimental allergic encephalomyelitis (EAE), an animal model resembling human multiple sclerosis (MS), there is evidence that T cells reactive to myelin basic protein mediate an inflammatory response within the central nervous system leading to demyelination. Furthermore, encephalitogenic T cells express TCR with highly restricted V gene usage and consequently specific forms of immunotherapy directed against V gene products have been successful in preventing and treating EAE. These findings prompted studies into the analysis of TCR repertoire expression in human autoimmune diseases in an attempt to identify the TCR usage of autoreactive and potentially pathogenic T cells. However, this has proved difficult as the autoantigens that drive the T cell response in most human autoimmune disorders are unknown. This review examines the data that have accumulated over the past few years on TCR usage in human autoimmune diseases and is focused largely on rheumatoid arthritis and MS.