Search

The question of whether there is a preferential use of certain V genes in T cells entering an inflamed joint has hitherto been studied mainly using unfractionated cells from synovial fluid and tissue respectively, and no clear answer to the question has yet been provided. Concomitantly, evidence has been provided that the use of V genes may differ considerably between CD4+ and CD8+ T cells, and consequently that detection of biased V-gene expression within an inflammatory lesion may require separate analysis of the two T-cell subsets. In this paper we have therefore studied T-cell receptor V-gene expression in rheumatoid arthritis by means of double stainings of synovial fluid and blood for available anti-TCR monoclonal antibodies and antibodies to CD4 and CD8, respectively. Double stainings were also performed with anti-TCR antibodies and antibodies to activation markers HLA-DR and IL-2R. A certain bias towards the preferential use of certain V genes was seen particularly in the synovial fluid samples within both the CD4+ and CD8+ T-cell populations, but no uniform pattern was evident among the 35 patients investigated.

A panel of monoclonal antibodies specific for TcR V gene families was used to study TcR V region expression in 28 cases of malignant and reactive T-cell expansions including four cases of mixed cellularity Hodgkin's disease (HD) and five reactive cases. TcR V beta 5 gene products were represented in three cases of lymphoblastic malignancy (V beta 5.1, V beta 5.2) and two cases of peripheral T-cell lymphoma (PTCL) (V beta 5.1). In the PTCL cases, the expanded family was found in the absence of clonal TcR gene rearrangements and in one of these cases with Ig JH and Ck clonal gene rearrangements consistent with the presence of a phenotypically and histologically undetectable clonal B-cell population. In a third PTCL case not investigated for genotype, the TCR V alpha 12 family was overrepresented. Expanded TcR V alpha 2 and V beta 5.1 families were identified in HD and V beta 8 and V beta 5.2/V beta 5.3 families in a reactive lymph node and CD3 and CD8-positive blood lymphocytosis respectively. Further study of PTCL and related entities are needed to establish whether expanded TcR families are common in those cases that fail to exhibit clonal TcR gene rearrangement.

We compared T cell receptor (TCR) V-segment frequencies in human leukocyte antigen (HLA) identical siblings to sibling pairs who differ at one or both HLA haplotypes using four V beta-specific and one V alpha-specific monoclonal antibody. In every one of nine families HLA-identical sibs had the most similar patterns of V-segment frequencies in their peripheral blood, whereas totally mismatched sibs were, in general, the most dissimilar; HLA haploidentical sibs tended to be intermediate between the two groups. The degree of similarity among HLA-identical sibs was comparable to that observed among three pairs of identical twins suggesting that HLA is the major genetic component influencing TCR V-segment frequency. Consistent with this observation, it was found that the frequency of T cells expressing particular V beta segments was skewed towards either CD4+ or CD8+ cells indicating that T cells expressing some V beta genes may be positively selected primarily by class I or class II major histocompatibility complex proteins. Finally, it was observed that individuals who express the HLA class I specificity, B38, tend to express high levels of V alpha 2.3+ cells among their CD8+ T cells. These observations represent definitive proof that human V-segment frequencies are profoundly influenced by the HLA complex.

The presence of T cells binding F(ab')2 fragments of the idiotypic immunoglobulin was examined by immunofluorescence in peripheral blood of patients with monoclonal gammopathy. In 3 out of 11 tested patients, 1-15% idiotype-binding T cells of either CD4 or CD8 phenotype were found. In 1 patient both a CD4+ and a CD8+ idiotype-binding T-cell fraction were present. In 1 patient the idiotype-binding T cells also reacted with a mAb directed against the variable parts of the TCR alpha or beta chains, further indicating a clonal origin at the alpha/beta level. 3 patients had an expanded predominant T-cell receptor V gene usage based on the reactivity with the limited panel of TCR mAb, but these "clonal" T cells did not bind the idiotype. The study supports the existence of idiotype-specific T cells in peripheral blood of patients with monoclonal gammopathy. Such cells might have a regulatory role on the monoclonal B-cell clone and may be an important target for immunotherapy.

To determine the extent of V-gene heterogeneity of blood T lymphocytes in patients suffering from Myasthenia Gravis (MG), we used eight recently available monoclonal antibodies (MoAb), directed against different V alpha and V beta gene products of the variable part of the T-cell receptor (TCR), covering approximately 25% of the alpha/beta T cells in normal peripheral blood (PBL) of healthy individuals. Using a two-colour immunofluorescence method, we could calculate the expression of alpha/beta V segments within the two major T-cell subsets, CD4-/CD8+ and CD4+/CD8- lymphocytes. Twenty-seven per cent (4/15) of the MG patients had T cells showing signs of abnormal expansion. Furthermore, among these expanded T cells, a restricted V beta 12 gene expansion could be seen, in three out of four patients. No correlation between TCR V-gene usage and HLA haplotypes (HLA-A, -B, -DR and -DQ) could be seen. Our data suggest that the majority of MG patients have abnormally expanded T-cell clones. The relevance of these findings is discussed.

We have examined alpha/beta V gene segment usage of peripheral blood CD4+ and CD8+ T cells, respectively, from patients with multiple myeloma and monoclonal gammopathy of undetermined significance, by using T cell receptor (TCR) for antigen monoclonal antibodies (MoAbs). In 7 of 16 patients we found an increase in the usage of various TCR V gene segments. The expansion was confined to either the CD4+ or the CD8+ T-cell subset, except for one patient where an abnormal pattern was observed both within the CD4+ and CD8+ T-cell subsets. In one patient 47%, and in another patient 30% of the CD8+ lymphocytes reacted with alpha V12.1 and beta V6.7 antibodies, respectively. In two other patients 29% and 40% of the CD4+ lymphocytes reacted with beta V6.7 and beta V8.1 antibodies, respectively. We conclude that T cells with a predominant V gene usage is a frequent feature in patients with abnormal clonal B cells of malignant or benign types. T- and B-cell populations are normally clonally linked in regulatory circuits. An abnormal proliferation of B cells might therefore induce, or be regulated by, an expansion of clonal T cells, as suggested by the present results.

The expression of seven different alpha and beta gene segments of the T cell receptor on normal human CD4+ and CD8+ T lymphocytes, respectively, was examined using V gene-specific monoclonal antibodies. We found a statistically significant (p less than 0.001) bias of the expression of four V gene products towards the CD4+ subpopulation. In every individual analyzed, the V beta 5.1 gene segment was expressed to a higher degree among CD4+ compared to CD8+ cells, with a median value of 4.8% among CD4+ cells and 1.5% among CD8+ cells. There was also a statistically significant skewness in the usage of the V beta 6.7, V beta 8 and V beta 12 gene segments towards the CD4+ T cell population, but not as dominating as for the V beta 5.1. Lymphocytes from umbilical cord blood showed similar skewed reactivities for the V beta 5.1, V beta 6.7 and V beta 12-specific monoclonal antibodies. Aspects of positive and negative selection, as possible explanations for these findings, are discussed.

Mouse monoclonal antibodies recognizing cell surface molecules on tumour cells from a patient with a T-cell chronic lymphatic leukaemia (T-CLL) have been produced. Three different types of idiotype-like cell surface structures were identified. One molecule had a relative molecular weight (Mr) of 90,000 under non-reduced conditions and of 42,000 upon reduction, which corresponds well to the T-cell receptor for antigen (Ti). The two other molecules, which also behaved like unique tumour markers, have not previously been described, to our knowledge. One molecule was a monomer with an Mr of 74,000-80,000 when non-reduced and 80,000 upon reduction. The other idiotypic molecule was a dimer with a non-reduced Mr of 74,000-80,000, and 38,000 after reduction.