T-cell Receptor Variable Beta Chain Research Articles

Compositional characteristics of human peripheral TRBV pseudogene rearrangements

The diversity of the T cell receptor (TCR) complementarity determining region 3 (CDR3) repertoire is the result of random combinations, insertions and deletions during recombination of the germline V, D and J gene fragments. During evolution, some human TCR beta chain variable (TRBV) pseudogenes have been retained. Many previous studies have focused on functional TRBV genes, while little attention has been given to TRBV pseudogenes. To describe the compositional characteristics of TRBV pseudogene rearrangements, we compared and analysed TRBV pseudogenes, TRBV open reading frames (ORFs) and functional TRBV genes via high-throughput sequencing of DNA obtained from the peripheral blood of 4 healthy volunteers and 4 patients. Our results revealed several differences in J and D gene usage. The V deletion distribution profile of the pseudogenes was significantly different from that of the ORFs and functional genes. In addition, arginine, lysine and cysteine were more frequently used in putative CDR3 pseudogene rearrangements, while functional rearrangements used more leucine. This study presents a comprehensive description of the compositional characteristics of peripheral TRBV pseudogene rearrangements, which will provide a reference for further research on TRBV pseudogenes.

Sex bias in MHC I-associated shaping of the adaptive immune system

HLA associations, T cell receptor (TCR) repertoire bias, and sex bias have independently been shown for many diseases. While some immunological differences between the sexes have been described, they do not fully explain bias in men toward many infections/cancers, and toward women in autoimmunity. Next-generation TCR variable beta chain (TCRBV) immunosequencing of 824 individuals was evaluated in a multiparametric analysis including HLA-A -B/MHC class I background, TCRBV usage, sex, age, ethnicity, and TCRBV selection/expansion dynamics. We found that HLA-associated shaping of TCRBV usage differed between the sexes. Furthermore, certain TCRBVs were selected and expanded in unison. Correlations between these TCRBV relationships and biochemical similarities in HLA-binding positions were different in CD8 T cells of patients with autoimmune diseases (multiple sclerosis and rheumatoid arthritis) compared with healthy controls. Within patients, men showed higher TCRBV relationship Spearman's rhos in relation to HLA-binding position similarities compared with women. In line with this, CD8 T cells of men with autoimmune diseases also showed higher degrees of TCRBV perturbation compared with women. Concerted selection and expansion of CD8 T cells in patients with autoimmune diseases, but especially in men, appears to be less dependent on high HLA-binding similarity than in CD4 T cells. These findings are consistent with studies attributing autoimmunity to processes of epitope spreading and expansion of low-avidity T cell clones and may have further implications for the interpretation of pathogenic mechanisms of infectious and autoimmune diseases with known HLA associations. Reanalysis of some HLA association studies, separating the data by sex, could be informative.

Utilizing IL-7 to generate melanoma antigen T cell receptor-modified cells for adoptive transfer in the absence of activation.

e14552 Background: Metastatic melanoma remains a fatal disease as many patients fail to respond to novel therapies. Presently, we have an ongoing trial utilizing T cell receptor (TCR)-modified cells reactive to the melanoma antigen, tyrosinase, for treatment of metastatic melanoma (NCT01586403). Current protocols using viral vectors to generate cells for adoptive transfer require activation in the presence of IL-2. While IL-2 stimulates proliferation and production of mature effector cells, it also induces T cell exhaustion. We hypothesize that tyrosinase-reactive TCR-modified cells generated in the absence of activation have an increased potential for expansion, persistence, and anti-melanoma activity. In these studies, we investigate whether IL-7, a homeostatic regulator, facilitates the transfer of a tyrosinase-reactive TCR to lymphocytes without activation. Methods: Gene-modified cells were generated using a lentiviral vector including alpha and beta chains of a TCR reactive to tyrosinase and a truncated CD34 molecule as a transduction marker. Peripheral lymphocytes from normal human donors were transduced with lentivirus following no treatment, treatment with IL-7, or activation in the presence of IL-2. Transduced CD34 positive cells were isolated using magnetic activated cell sorting (MACS) and injected intravenously into NOD scid gamma (NSG) mice. Results: We found that IL-7 treatment improved transduction in non-activated cells and resulted in expression levels of CD34 and TCR variable beta chain 12 (vbeta12) comparable to cells activated in the presence of IL-2. When non-activated tyrosinase-reactive TCR-modified human T cells were adoptively transferred into NOD NSG mice, the cells were detectable in the peripheral blood of mice up to 7 days after transfer. Conclusions: These findings suggest that generating melanoma antigen TCR-modified cells in the absence of activation for adoptive transfer is feasible with IL-7 treatment. Ongoing studies in NSG mice transplanted with melanoma will help determine whether non-activated gene-modified cells will improve the efficacy and longevity of cell therapy for melanoma and other malignancies.

The frequency and skewed T-cell receptor beta-chain variable patterns of peripheral CD4+CD25+ regulatory T-cells are associated with hepatitis B e antigen seroconversion of chronic hepatitis B patients during antiviral treatment

The frequency and T-cell receptor beta-chain variable (TCRBV) patterns of peripheral CD4(+)CD25(+) regulatory T-cells (Tregs) are ambiguously altered in chronic hepatitis B (CHB) patients following tenofovir disoproxil fumarate (TDF) treatment. Moreover, the clinical significance of these parameters in relation to hepatitis B e antigen (HBeAg) seroconversion (SC) is largely unknown. In this study, the circulation of Tregs in HBeAg-positive CHB patients was determined by flow cytometry, and the molecular profiles of frequent TCRBV patterns of Tregs were analyzed using a gene melting spectral pattern. The parameters, such as Treg frequency, the number of skewed TCRBV patterns, hepatitis B virus (HBV) DNA levels, and alanine aminotransferase (ALT) levels, were analyzed by comparing their associations in seroconverting and non-seroconverting patients following TDF treatment. The Treg frequency was significantly correlated with the ALT level in seroconverting but not in non-seroconverting patients. Similarly, skewed TCRBV patterns were remarkably associated with HBV DNA levels in the SC group. Six TCRBV families (BV3, BV11, BV12, BV14, BV20, and BV24) were more prevalent than other TCRBV members in seroconverting patients pretreated with TDF, while BV12, BV15, and BV22 were predominant in non-seroconverting patients during TDF treatment. Taken together, the preferential TCRBV patterns may be associated with immune responses related to SC. The dynamic frequency and skewed TCRBV patterns of peripheral Tregs could contribute to predicting SC in CHB patients. Moreover, the conserved TCRBV complementarity-determining region (CDR3) motif may be targeted to develop personalized immunotherapy for CHB patients.

Profiling the repertoire of T-cell receptor beta-chain variable genes in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection.

The profile of T-cell receptor beta-chain variable (TRBV) genes usually skews in subjects with virus infection or cancer. The gene melting spectral pattern (GMSP) can be used to determine the profile of the TRBV gene family. To explore the portrait of the TRBV family in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection (AHI), peripheral blood mononuclear cells (PBMCs) were separated and further sorted into CD4+ and CD8+ T-cell subsets. The molecular features of the TRBV complementary determining region 3 (CDR3) motifs were determined using GMSP analysis. When aGMSP profile showed a single peak, the monoclonally expanded TRBV gene was cloned and sequenced. Skewed expansions of multiple TRBV genes were observed among the CD4+ and CD8+ T-cell subsets and the PBMCs. The frequency of monoclonally expanded TRBV genes in the CD8+ T-cell subset was significantly higher than that of the CD4+ T-cell subset and the PBMCs. Compared to other members of the TRBV gene family, TRBV11, BV15 and BV20 were predominantly expressed in the repertoire of peripheral blood lymphocytes in recovered AHI subjects. The relatively conserved amino acid motifs of TRBV5.1 and BV20 CDR3 were also detected in the CD4+ and CD8+ T-cell subsets. These results demonstrate the presence of multiple biased TRBV families in recovered AHI subjects. TRBV11, BV15 and BV20, especially from the CD8+ T-cell subset, may be relevant to the pathogenesis of subjects with AHI. The preferentially selected TRBV5.1 and BV20 with the relatively conserved CDR3 motif may be potential targets for personalized treatments of chronic HBV infection.

Rapid detection of clonal expansion of T‐cell receptor‐beta gene in patients with HBV using the real‐time PCR with DNA melting curve analysis

The gene melting spectral pattern (GMSP) of PCR products from 24 T-cell receptor beta chain variable (TCRBV) gene families was developed to determine sequence bias and feature of TCRBV CDR3 gene family. The assay was based on reverse transcript quantitative polymerase chain reaction and their DNA melting curves. We discovered that the relatively conserved amino acid sequences X-Q and X-G are present in TCRBV CDR3 from patients with HBV. Further, the X of the X-Q motif is preferentially E (glutamic acid), P (proline) or T (threonine) when accompanied by the BJ2.7, BJ1.5, or BJ2.3, respectively. The frequency of sequence bias in the TCRBV gene family showed a positive correlation with the T cell receptor excision circles (TRECs) content, and an inverse correlation with the HBV DNA loading. These results suggest that the GMSP assay could be used to monitor the features of TCRBV gene distribution quickly, and facilitate the further study of HBV-specific T cell in patients with HBV.

Dynamic monitoring the TCR CDR3 spectratypes in patients with metastatic CRC treated with a combination of bevacizumab, irinotecan, fluorouracil, and leucovorin.

In the present study, either modified IFL regimen (modified irinotecan, fluorouracil and leucovorin, mIFL) alone or in combination with bevacizumab was used to treat patients with metastatic colorectal cancer (CRC). Treatment efficacy was assessed using coupled tomography imaging diagnosis. The toxicity accompany with treatment was evaluated, as well as T cell receptor (TCR) repertoire before and several cycles after therapy was dynamically monitored by analyzing the complementarity-determining region 3 (CDR3) length distribution within CD4(+) and CD8(+) T cell subsets. The degrees of normalization of the T cell repertoire in CRC patients treated with the two methods were compared. The results showed that mIFL combined with bevacizumab was more effective in treating patients with metastatic CRC, and was accompanied by an increase in side effects such as proteinuria and hematuria. An even more restricted CDR3 profile in patients with metastatic CRC compared with healthy control has been detected. A prominent usage of TCR beta chain variable (BV) gene BV12 and BV16 families within the CD4(+) T cell subset and BV19 and BV21 families within the CD8(+) T cell subset have been found before treatment. Moreover, CD8(+) T cells showed more restricted patterns than CD4(+) T cells, especially in patients before treatment. For patients with stable disease (SD) or partial remission (PR) after treatment, a less restricted CDR3 profile in post-treatment compared with pre-treatment has been found, but the opposite result was observed for patients with progressive disease (PD). The less restricted CDR3 pattern suggested a trend toward normalization of the TCR repertoire. The normalization of TCR repertoire significantly increased in patients treated with mIFL in combination with bevacizumab, but slightly in patients treated with mIFL alone. The results demonstrate a positive correlation between post-therapy TCR repertoire normalization and remission of metastatic CRC.

Individual and common antigen-recognition sites of liver-derived T cells in patients with autoimmune hepatitis.

Autoimmune hepatitis (AIH) is characterized by dense T-cell infiltrations in the liver tissue, but little is known how T cells influence the pathogenesis. To address this question, the distribution of T-cell receptor variable beta-chain (TCR Vbeta) transcripts of peripheral blood and liver-infiltrating T cells from previously untreated patients with newly diagnosed acute exacerbated AIH was investigated. Furthermore, the lengths and sequences of complementary-determining region 3 (CDR3) were studied. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and CDR3 spectratyping revealed multiple clonal expansions of liver-infiltrating T cells but not peripheral T cells within various TCR Vbeta families. Further analysis of overexpressed TCR Vbeta transcripts using TCR beta-chain-joining element (TCR Jbeta)-specific primers in a nested PCR showed characteristic Vbeta/Jbeta combinations. Subsequent sequencing of CDR3 regions from PCR products confirmed the clonality of T-cell expansions and the usage of common and individual CDR3 motifs. In conclusion, the clonality of expanded T cells within the liver tissue during early clinical manifestation of untreated AIH indicated that autoantigen-specific T cells accumulate at the inflammation site. Individual and common CDR3 motifs argued for predominant epitopes that were recognized by liver-infiltrating T cells in AIH patients.

The functional CD8 T cell response to HIV becomes type-specific in progressive disease.

High levels of HIV-specific CD8 T cells are demonstrable throughout HIV disease using laboratory assays that measure responses to consensus epitopes. In acute infection, the dynamics of the antiviral CD8 T cell response correlate well with the decline in viremia. However in chronic infection, although responses are detected against a broader spectrum of epitopes, virus-specific CD8 T cells are apparently unable to control viral replication. To investigate whether CD8 T cells responding to consensus epitopes may have lost their in vivo relevance in the chronic phase because of viral evolution driven by immune pressure, we compared the CD8 T cell response to CD4 T cell targets infected with either lab-adapted HIV(IIIB) or the patient's own virus. The magnitude of the IFN-gamma response declined with disease progression, especially to autologous virus. T cell receptor (TCR) clonotypes of HIV(IIIB) and autologous virus-responding cells were determined by sequencing TCR beta chain variable (TCRBV) genes. In two of three asymptomatic donors, the dominant clonotypes overlapped, whereas in five symptomatic patients, the TCR clonotypes responding to HIV(IIIB) virus were completely different from those responding to autologous virus. Moreover, in cytolytic assays, T cell lines derived from IFN-gamma(+) cells responding to lab-adapted or autologous virus cross-recognized target cells infected with either virus in asymptomatic subjects with shared TCR clonotypes but not in progressors with differing clonotypes. Therefore, in advanced-stage patients, viral-specific CD8 T cells recognizing consensus epitopes persist from an earlier response but no longer effectively recognize autologous virus.

Evidence of clonotypic pattern of T-cell repertoire in synovial fluid of children with juvenile rheumatoid arthritis at the onset of the disease.

Rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) are characterized by chronic inflammation, synovial cell proliferation and progressive joint damage. It has been speculated that T cells play an important role in the pathogenesis of RA and JRA in the early stage of the disease. Previous studies have demonstrated discrepant results regarding the significance of T-cell clonality in RA or JRA lesions. It can be postulated that the heterogeneity of these data may be linked to the stage of the disease, as the relative importance of selective immunological events is different during the time from onset to established disease. To avoid this problem, we conducted the present study in nine children affected by JRA at the onset of the disease and before treatment. We analysed the T-cell receptor beta chain variable (TCRBV) of CD4+ and CD8+ lymphocytes in peripheral blood (PBL) and synovial fluid (SFL), by a panel of monoclonal antibodies (MoAbs). Furthermore, to assess the clonotypic pattern of T-cell repertoire, the CDR3 length distribution was evaluated by spectratyping analysis. Our results showed no significant expansion of distinct TCRBV subset in either synovial or peripheral compartments. Conversely, when we studied the CDR3 length distribution, an oligoclonal pattern was found in the SFL of six patients, suggesting the presence of a clonotypic restriction of T cells in SFL, which is not detectable in PBL. These findings are consistent with an antigen driven T-cell expansion sequestered at the inflammatory site.

Persistence of clonal T-cell expansions following high-dose chemotherapy and autologous peripheral blood progenitor cell rescue

Analysing the regeneration of T lymphocytes after high-dose chemotherapy with autologous peripheral blood progenitor cell rescue (PBPCR) may help elucidate the mechanisms of immune recovery. The T-cell receptor variable beta chain (TCRBV) repertoire of adult patients undergoing high-dose chemotherapy was analysed by flow cytometry, before and after treatment. Four patients were found to have a stable expansion present (TCRBV3, 17, 21 and 22) ranging from 8% to 42% of the CD4(+) or CD8(+) repertoire. We demonstrated that, in these patients, following high-dose chemotherapy and autologous stem cell transplantation, the clonal expansions reappeared in peripheral blood and returned to pretransplant levels. Three expansions (CD3(+)CD8(+)TCRBV3(+), CD3(+)CD4(+)TCRBV21(+) and CD3(+)CD8(+)TCRBV22(+)) were further defined by sequence analysis of the complementarity-determining region (CDR)3 portion within the TCR rearrangements. These were shown to be predominantly clonal, with the same sequences being identified in peripheral blood before and after PBPCR, providing evidence that the overwhelming majority of T cells in these expansions arise from mature lymphocytes. This study demonstrated that patients undergoing autologous PBPCR for high-dose chemotherapy regenerate clonal expansions, consistent with pretreatment levels. They also regenerate T-cell repertoires with each TCRBV family represented to a similar level as that prior to high-dose chemotherapy.

Clonal expansion of T lymphocytes in human melanoma metastases after treatment with a hapten-modified autologous tumor vaccine.

Metastatic melanoma patients treated with an autologous DNP-modified tumor cell vaccine develop inflammatory responses in metastatic tumors characterized by infiltration of CD8+ T cells. To further define this immune response, we analyzed T cell receptor beta-chain variable (TCRBV) region repertoire in biopsy specimens and peripheral blood lymphocytes of six patients. After administration of DNP vaccine, a restricted set of TCRBV gene families was found to be expanded compared with prevaccine metastases. In several postvaccine lesions of one patient, obtained over a 2-yr period, TCRBV14+ T cells were clonally expanded and identical T cell clonotypes could be detected. Two major recurring clones were biased toward the use of TCRBJ1S5. Furthermore, T cell lines derived from two such infiltrated skin lesions and, enriched in TCRBV14+ T cells, displayed HLA-class I-restricted lysis of the autologous melanoma cells. Clonal expansion of T cells was demonstrated in the T cell-infiltrated, postvaccine metastasis of a second patient as well. These results indicate that vaccination with autologous, DNP-modified melanoma cells can expand selected clones of T cells at the tumor site and that such clones are potentially destructive to the tumor.

Possible mechanism for the TCR beta-chain associated EAE resistance of LER rats.

LER rats are resistant to the active induction of experimental allergic encephalomyelitis (EAE). The mechanism of their resistance to EAE has yet to be defined, although LER rats are susceptible to adoptively transferred EAE. Genetic analysis of LER and the susceptible LEW rat suggests that a gene linked to the T cell receptor (TCR) beta-chain complex contributes to EAE resistance. This result is consistent with the fact that EAE is a T cell mediated disease and one characterized in EAE-susceptible animals by an oligoclonal TCR V beta 8.2+ response. In this report, analysis of TCR transcripts by reverse transcriptase polymerase chain reaction (RT-PCR) and restriction digestion demonstrates that LER lymph nodes, collected on day 10 post-immunization with myelin basic protein (MBP), express both TCR-V beta 8.2 and other TCR beta chains, usually V beta 8.4, whereas LEW animals demonstrate preferential and almost exclusive use of V beta 8.2 TCR. Fluorescence-activated cell sorting (FACS) analyses of anti-MBP T cells confirm that LER T cells express V beta 8.2 TCR to a lesser degree than LEW T cells. Finally, experiments examining the oligo- or polyclonality of the TCRV beta CDR3 region show that the LER response to MBP is polyclonal, while the LEW response to MBP is oligoclonal. Therefore, the cumulative data on the TCR usage profiles in this report suggest that the choice of TCR variable beta-chain may contribute to the resistance seen in the LER rat.

The potential role of bacterial superantigens in the pathogenesis of Kawasaki syndrome.

Kawasaki syndrome is an acute multisystem vasculitis of infancy and early childhood associated with high fever, mucocutaneous inflammation, and the development of coronary artery abnormalities. Despite the widely held belief that Kawasaki syndrome is an infectious disease, investigations have failed to identify a causal organism. Previous studies have demonstrated that this illness is associated with marked activation of monocyte/macrophages and the selective expansion of V beta 2-, less so, of V beta 8.1/8.2-expressing T cells in the peripheral blood from Kawasaki syndrome patients during the acute phase of their illness. These immunologic features are characteristic of diseases that are caused by bacterial toxins which act as superantigens. Staphylococcal enterotoxins and streptococcal exotoxins are prototypic superantigens which stimulate large populations of T cells expressing particular T-cell receptor beta-chain variable (V beta) gene segments. Using the V beta 2+ T-cell expansion as an "immunologic footprint" for a superantigen, we have extended these observations to the identification and isolation of a novel clone of toxic shock syndrome toxin-1-producing Staphylococcus aureus in the majority of patients with Kawasaki syndrome and streptococcal pyrogenic exotoxin B/streptococcal pyrogenic exotoxin C-producing streptococci in a minority of Kawasaki syndrome patients. Toxic shock syndrome toxin-1, streptococcal pyrogenic exotoxin B, and streptococcal pyrogenic exotoxin C are known to stimulate V beta 2+ T cells. These observations support the hypothesis that the activation of V beta 2+ T cells during the acute phase of Kawasaki syndrome is caused by bacterial superantigen(s).

Correlation between cellular rejection of cardiac allografts and quantitative changes among T-cell subsets identified by V beta epitope expression.

Cellular rejection of an allograft is mediated in part by peripheral blood T cells. We tested the hypothesis that quantitative changes in T-cell subsets can be detected in the peripheral blood and that these changes correlate with rejection. T-cell subset analysis was performed by flow cytometry using monoclonal antibodies recognizing six isotypic epitopes of the T-cell receptor beta-chain variable (V) region. These analyses were done at 7-day (mean) time intervals. Fluctuations within a given subset were determined by dividing the number of positive cells observed by the number of positive cells found on the previous analysis. For healthy volunteers observed over a period of 30 days, 119 of 120 subset ratios (99.2%) fell between 0.5 and 2.0. For patients, 57 of 240 subset ratios (23.8%) fell outside of this range (P < .004, chi 2). The occurrence of the abnormal ratios coincided more closely with cellular rejection (mean +/- SD, 7.7 +/- 6.2 days from a positive biopsy; median, 5 days; range, 0 to 28 days) than did the occurrence of normal subset ratios (mean +/- SD, 14.4 +/- 10.9 days from a positive biopsy; median, 11 days; range, 0 to 44 days; P < .005 by Mann-Whitney U test). Regression analysis confirmed a significant (P < .001, R = .91) temporal association between cellular rejection and abnormal subset fluctuations. No correlation was found between abnormal subset ratios and either vascular rejection or use of high-dose prednisone. T-cell subset measurement may be a method of noninvasive monitoring of cellular rejection after transplantation and may provide insights into the physiology of graft rejection with the potential for the development of more specific immunosuppressive therapy.

T cells expressing variable elements of T-cell receptor beta 8 and beta 2 chain regulate murine IgE production.

After sensitization to ovalbumin (Ova) by inhalation of nebulized antigen, BALB/c mice respond with an early rise in IgE but not in IgG anti-Ova antibody production. Our purpose here was to analyze the repertoire of T cells that may contribute to regulating this IgE response. Initial study of Ova-reactive T-cell hybridomas showed that they selectively express the T-cell receptor variable beta-chain (V beta) elements 2, 8.1/8.2, and 14. The frequency of T cells bearing these V beta elements in local draining lymph nodes of the airways and lungs (peribronchial-draining lymph nodes) after Ova inhalation was examined. Local sensitization increased the proportion of V beta 8.1/8.2 T cells in the peribronchial-draining lymph nodes, whereas expression of V beta 2 or V beta 14 was similar in sensitized and nonsensitized animals. In the presence of increased antigen concentrations, V beta 8 and V beta 2 T cells were equally reactive to Ova when cell proliferation was assayed. Coculture of Ova-selected V beta 8 T cells from peribronchial-draining lymph nodes and spleens of sensitized animals with primed splenic B cells increased IgE but not IgG production. The V beta 8 increase in IgE production was related to an increase in numbers of IgE-secreting B cells. In contrast, coculture of Ova-selected V beta 2 T cells with sensitized B cells had no stimulatory effect on either IgE or IgG production. Further, addition of V beta 2 cells to V beta 8 cells inhibited the V beta 8-induced augmentation of IgE production. These data indicate that T cells expressing different T cell receptors or, perhaps, different V beta elements may play different roles in IgE production in sensitized mice.

Selective expansion of T cells expressing T-cell receptor variable regions V beta 2 and V beta 8 in Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis complicated by the development of coronary artery abnormalities. The etiology of KD is unknown. Based on the observation that KD is associated with marked activation of T cells and monocyte/macrophages, we hypothesized that KD may be caused by a superantigen [e.g., a bacterial toxin that stimulates T cells expressing particular T-cell receptor beta chain variable (V beta) gene segments]. Peripheral blood T cells from patients in the acute and convalescent phases of KD and from various control groups were analyzed for T-cell receptor V beta gene expression by using a quantitative PCR technique and cytofluorographic analysis with available anti-V beta monoclonal antibodies. Patients with acute KD demonstrated significantly elevated levels of circulating V beta 2+ and V beta 8.1+ T cells compared to the other control groups. none of the other 20 V beta populations analyzed by quantitative PCR were found to be significantly elevated. Using flow cytometry, we confirmed a significant elevation of T cells reactive with anti-V beta 8.1 and the lack of change in several other V beta subsets--i.e. V beta 5.1, -5.2, -6.7, and -12. During the convalescence phase of KD, there was a reduction in the abnormal levels of V beta 2+ and V beta 8.1+ T cells. These observations suggest that KD may be caused by a superantigen and may provide insight into the nature of the etiologic agent.

T-cell receptor variable region gene expression in cutaneous T-cell lymphomas.

The cutaneous T-cell lymphomas (CTCL) are a group of diseases characterized by malignant proliferations of CD4 positive T-cells having monoclonally rearranged T-cell receptor (TCR) genes. A recent study using monoclonal antibodies to two TCR beta-chain variable (V) region gene products showed preferential expression of the V beta 8 gene product in these tumors. The finding of predominant usage of a single V beta gene would imply that selection by antigen is important in the etiology of these tumors. We have studied eight cases of cutaneous T-cell lymphoma and one cell line derived from a patient with mycosis fungoides/Sezary syndrome, using an extended panel of antibodies to V region gene products. Contrary to the previous report, in our study expression of the V beta 8 gene product by tumor cells was not observed in any of the cases of CTCL or in the tumor cell line studied; preferential use of any of the variable region genes recognized by the antibodies in the panel was not observed.

A third T-cell receptor beta-chain variable region gene encodes reactivity to Mls-1a gene products.

Using a quantitative RNA hybridization method, we have identified a third murine T-cell receptor beta-chain variable (V) region gene, V beta 9, that engenders recognition of Mls-1a gene products. V beta 9-expressing T cells are clonally deleted from the periphery of mice that carry the Mls-1a allele, and the fine specificity of V beta 9+ hybridomas suggests that V beta 6-, V beta 8.1-, and V beta 9-encoded T-cell receptors may recognize a similar antigenic epitope. Comparison of these three protein sequences identifies two residues that may be important in determining this recognition specificity.