Specific Cytotoxicity and Clonal Expansion of TCR Vβ Subfamily T Cells Induced by PML-RARα Peptide.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3904-3904
Author(s):  
Yangqiu Li ◽  
Ji Tang ◽  
Lijian Yang ◽  
Shaohua Chen ◽  
Yubing Zhou
Keyword(s):  
T Cells ◽  
Cord Blood ◽  
Mononuclear Cells ◽  
Statistical Significance ◽  
Clonal Expansion ◽  
Cell Receptor ◽  
Control Group ◽  
Effector Cells ◽  
Specific Cytotoxicity

Abstract The analysis of T cell receptor (TCR) Vβ repertoire is one of the sensitive methods to identify the clonal expansion T cells which response to tumor associated antigens. Understanding the clonality and restricted usage of TCR Vβ repertoire of expanded T-cells induced by PML-RARα peptide may be useful in helping design the new immunotherapeutic strategy specifically for acute promyelocytic leukemia (APL).The aim of the present study was to investigate the specific cytotoxicity and clonality of TCR Vβ repertoire in cord blood T cells induced by PML-RARα peptide (LSSCITQGKAIETQSSSSEE) in vitro. Cord blood mononuclear cells were amplified by IL-2, anti-CD3 and anti-CD28 antibody with different concentration (16.7μg /ml, 33.3μg /ml or 50μg /ml respectively) of synthetic PML-RARα peptide. The induced T cells were collected at different time points after culture (3, 6, 9, 10, 12 or 15 days). The expression and clonality of TCR Vβ subfamilies within induced T cells were analyzed by using RT-PCR and genescan technique. The cytotoxicity of induced T cells was detected by LDH release assay. The results showed that the best condition for T cells induction and amplication was at a concentration with 16.7μg /ml of PML-RARα peptide and at a culture duration with 10 to 15 day. TCR Vβ repertoire analysis showed that restricted expression and cloanl expansion of TCR Vβ subfamily cord blood T cells could be identified after induction by PML-RARα peptide. Clonal expanded T cells were found in Vβ13, Vβ14 and Vβ16 subfamlies respectively. The induced T cells were showed to have the specific cytotoxicity for NB4 cell line (effector cells: tagerted cells=20:1), the cytotoxicity rates were 49.65±6.7% (p<0.05) at day 10th and 73.13±8.42% (p<0.01) at day 15th after culture, which show statistical significance in compare to the control group (without PML-RARα induction). In conclusions, the PML-RARα peptide could induce the clonal expansion T cells from cord blood in vitro, which may have specific cytotoxicity for PML-RARα+ cells.

scholarly journals Generation of Multiplexed Engineered, Off-the-Shelf CAR T Cells Uniformly Carrying Multiple Anti-Tumor Modalities to Prevent Tumor Relapse

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 11-11
Author(s):  
Chiawei Chang ◽  
Eigen Peralta ◽  
Gloria Hsia ◽  
Bi-Huei Yang ◽  
Wen-I Yeh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Fold Increase ◽  
Cell Receptor ◽  
Control Group ◽  
Antigen Specificity ◽  
Car T Cells ◽  
Car T ◽  
Specific Cytotoxicity

The development of chimeric antigen receptor (CAR) T cell therapeutics is widely recognized as a significant advancement for the treatment of cancer. However, several obstacles currently impede the broad use of CAR T cells, including the inherent process variability, cost of manufacturing, the absolute requirement for precise and uniform genetic editing in the allogeneic setting, and the challenge to keep pace with clonal heterogeneity and tumor growth. Utilizing our previously described induced pluripotent stem cell (iPSC)-derived T (iT) cell platform, we illustrate here the unique ability to address these challenges by creating a consistent CAR iT cell product that can be repeatedly manufactured in large quantities from a renewable iPSC master cell bank that has been engineered to mitigate the occurrence of graft versus host disease (GvHD), antigen escape and tumor relapse. Utilizing our proprietary cellular reprogramming and engineering platform and stage-specific T cell differentiation protocol, we demonstrate that iPSC can be engineered at the single cell level to generate a fully characterized clonal iPSC line, which can then be accessed routinely to yield CAR iT cells in a highly scalable manufacturing process (>100,000 fold expansion). Through bi-allelic targeting of a CAR into the T cell receptor alpha constant (TRAC) region, we generated CAR iT cells with uniform CAR expression (99.0 ± 0.5% CAR+) and complete elimination of T cell receptor (TCR) expression to avoid GvHD in the allogeneic setting. We elected to utilize the 1XX-CAR configuration, which has demonstrated superior anti-tumor performance relative to other CAR designs and when introduced into iT cells displayed enhanced antigen specificity (% specific cytotoxicity at E:T=10:1, antigen positive group: 86.4 ± 7.8; antigen null group: 8.9 ± 3.5). To enhance persistence without reliance on exogenous cytokine support, we engineered signaling-fusion complexes, including IL-7 receptor fusion (RF), into iPSC and studied its impact on iT phenotype, persistence, and efficacy. In vitro, IL-7RF clones demonstrated improved anti-tumor activity in a serial antigen dependent tumor challenge assay (Day 10, relative tumor counts, IL-7RF group: 1.95 ± 0.01; control group: 57.56 ± 4.55, P<0.000001). In a preclinical in vivo model of disseminated leukemia, IL-7RF clones demonstrate enhanced tumor growth inhibition (Day 34, Log [BLI], IL-7RF group: 6.68 ± 1.93; control group: 9.99 ± 0.23, P=0.0143). We next investigated a unique strategy to incorporate multi-antigen targeting potential into anti-CD19 1XX CAR iT cells with the addition of a high-affinity non-cleavable CD16 (hnCD16) Fc receptor. The combination of hnCD16 with anti-CD19 1XX CAR culminated in iT cells capable of multi-antigen specificity through combinatorial use with monoclonal antibodies to tackle antigen escape. Utilizing CD19 negative leukemia cells as targets, superior antibody-dependent cellular cytotoxicity (ADCC) was demonstrated by the combination of hnCD16 CAR iT and Rituximab (% specific cytotoxicity at E:T=1:1, hnCD16 group + Rituximab: 75.64 ± 2.12; control group + Rituximab: 16.98 ± 3.87, P<0.001). To address T cell fitness, the role of CD38 knockout (KO) in T cells was investigated, which we have previously shown to mediate NK cell resistance to oxidative stress induced apoptosis. CD38 gene was disrupted at the iPSC stage to generate 1XX-CAR T cells that lack CD38 expression (% CD38+ population, CD38WT group: 69.67 ± 24.34; CD38KO group: 0.12 ± 0.11) and upon antigen mediated stimulation, CD38KO CAR iT cells showed higher percentages of degranulation (2.3-fold increase in CD107a/b), and IFNγ (4.1-fold increase) and TNFα (2.5-fold increase) production. Antigen specific in vitro tumor killing also was enhanced in CD38KO CAR iT cells (EC50, 3.2-fold decrease). Lastly, to avoid the potential host-mediated rejection, the inclusion of allogeneic defense receptor (ADR) which has been shown to significantly reduce host-mediated rejection will be discussed. Collectively, the described studies demonstrate that iPSCs are an ideal cellular source to generate large-quantities of uniformly multi-edited off-the-shelf CAR T cell products that include a best-in-class CAR design, enhanced product modalities, and complete elimination of TCR expression to avoid the potential of GvHD while maintaining high anti-tumor efficacy in allogeneic setting. Disclosures Hsia: Fate Therapeutics Inc.: Current Employment. Clarke:Fate Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Lee:Fate Therapeutics, Inc.: Current Employment. Robbins:Fate Therapeutics, Inc.: Current Employment. Denholtz:Fate Therapeutics, Inc: Current Employment. Hanok:Fate Therapeutics, Inc.: Current Employment. Carron:Fate Therapeutics, Inc.: Current Employment. Navarrete:Fate Therapeutics, Inc.: Current Employment. ORourke:Fate Therapeutics, Inc.: Current Employment. Sung:Fate Therapeutics, Inc.: Current Employment. Gentile:Fate Therapeutics, Inc.: Current Employment. Nguyen:Fate Therapeutics, Inc.: Current Employment. Valamehr:Fate Therapeutics, Inc: Current Employment, Current equity holder in publicly-traded company.

Oligoclonal Expansion of TCR V beta Subfamily T Cells in Patients with B-ALL.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3840-3840
Author(s):  
Yangqiu Li ◽  
Meijuan Huang ◽  
Yubing Zhou ◽  
Shaohua Chen ◽  
Lijian Yang
Keyword(s):  
T Cells ◽  
Peripheral Blood ◽  
Cell Clone ◽  
Clonal Expansion ◽  
Gene Repertoire ◽  
Peripheral Blood Mononuclear ◽  
Tumor Associated Antigen ◽  
Specific Cytotoxicity ◽  
Pcr Products

Abstract Clonal expansion of TCR V beta subfamily T cells were identified in peripheral blood and tumor infiltrated tissues lymphocytes from some solid tumors and leukemias, which were thought to be relative to tumor associated antigen and be benefited for design of the strategy of specific immunotherapy. The aim of this study is to investigate the situation of TCR V beta gene repertoire and clonal expansion in peripheral blood T cells from patients with B-ALL. The complementarity determining region 3 (CDR3) of TCR V beta 24 subfamily genes in peripheral blood mononuclear cell from 13 cases with untreated B-ALL were amplified using RT-PCR. The PCR products were further labelled by fluorescein and then analyzed by genescan technique for detection of the CDR3 size, to determine the clonality of T cells. The results showed that only 2–18 V beta subfamilies were identified in 13 B-ALL cases respectively. The frequency expression of V beta subfamilies was V beat 13 (84.6%) and V beta 21 (76.9%). No positive products were detected in V beta 4, 6, 8, 18, 20 and V beta 24 subfamilies. Clonal expansive T cells in one or more V beta subfamilies were found in all 13 cases. The display frequency of clonal expansive T cells in V beta 21 (46.1%) and V beta 23 (30.8%) subfamilies were higher than others. In conclusions, the results indicated that the dominant utilization of TCR V beta repertoire could be found in peripheral blood T cells from patients with B-ALL, meanwhile clonal expansive T cells were existed. It may be a feature of the host immune response for leukemia associated antigen. The clonal expansive tendency of T cells in V beta 21 and V beta 23 subfamilies was rather obvious, which maybe correlated with certain malignant B-cell clone. Isolation and amplification of the clonal expanded V beta T cells in vitro may be necessary for identification of the specific cytotoxicity for leukemia cells.

Roscovitine Prevents TCR-Mediated T Cell Clonal Expansion In-Vitro and Protects Against GvHD In-Vivo.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 318-318 ◽  
Author(s):  
Lequn Li ◽  
Hui Wang ◽  
Vassiliki A. Boussiotis
Keyword(s):  
Cell Cycle ◽  
T Cells ◽  
T Cell ◽  
Bone Marrow Cells ◽  
T Cell Responses ◽  
Clonal Expansion ◽  
Control Group ◽  
Cell Responses

Abstract Cell cycle re-entry of quiescent T lymphocytes is required for generation of productive T cell responses. Cyclin-dependent kinases (cdk), particularly cdk2, have an essential role in cell cycle re-entry. Cdk2 promotes phosphorylation of Rb and related pocket proteins thereby reversing their ability to sequester E2F transcription factors. Besides Rb, cdk2 phosphorylates Smad2 and Smad3. Smad3 inhibits cell cycle progression from G1 to S phase, and impaired phosphorylation on the cdk-mediated sites renders it more effective in executing this function. In contrast, cdk-mediated phosphorylation of Smad3 reduces Smad3 transcriptional activity and antiproliferative function. Recently, we determined that induction of T cell tolerance resulted in impaired cdk2 activity, leading to reduced levels of Smad3 phosphorylation on cdk-specific sites and increased Smad3 antiproliferative function due to upregulation of p15. We hypothesized that pharmacologic inhibition of cdk2 during antigen-mediated T cell stimulation might provide an effective strategy to control T cell expansion and induce tolerance. (R)-roscovitine (CYC202) is a potent inhibitor of cdk2-cyclin E, which in higher concentrations also inhibits other cdk-cyclin complexes including cdk7, cdk9 and cdk5. It is currently in clinical trials as anticancer drug and recently was shown to induce long-lasting arrest of murine polycystic kidney disease. We examined the effect of roscovitine on T cell responses in vitro and in vivo. We stimulated C57BL/6 T cells with anti-CD3-plus-anti-CD28 mAbs, DO11.10 TCR-transgenic T cells with OVA peptide or C57BL/6 T cells with MHC disparate Balb/c splenocytes. Addition of roscovitine in these cultures resulted in blockade of cell proliferation without induction of apoptosis. Biochemical analysis revealed that roscovitine prevented phosphorylation of cdk2, downregulation of p27, phosphorylation of Rb and synthesis of cyclin A, suggesting an effective G1/S cell cycle block. To determine whether roscovitine could also inhibit clonal expansion of activated T cells in vivo, we employed a mouse model of GvHD. Recipient (C57BL/6 x DBA/2) F1 mice were lethally irradiated and were subsequently infused with bone marrow cells and splenocytes, as source of allogeneic T cells, from parental C57BL/6 donors. Roscovitine or vehicle-control was given at the time of allogeneic BMT and on a trice-weekly basis thereafter for a total of three weeks. Administration of roscovitine protected against acute GvHD resulting in a median survival of 49 days in the roscovitine-treated group compared to 24 days in the control group (p=0.005), and significantly less weight loss. Importantly, roscovitine treatment had no adverse effects on engraftment, resulting in full donor chimerism in the treated mice. To examine whether tolerance had been induced by in vivo treatment with roscovitine, we examined in vitro rechallenge responses. While control C57BL/6 T cells exhibited robust responses when stimulated with (C57BL/6 x DBA/2) F1 splenocytes, responses of T cells isolated from roscovitine-treated recipients against (C57BL/6 x DBA/2) F1 splenocytes were abrogated. These results indicate that roscovitine has direct effects on preventing TCR-mediated clonal expansion in vitro and in vivo and may provide a novel therapeutic approach for control of GvHD.

scholarly journals In vitro priming and expansion of cytomegalovirus-specific Th1 and Tc1 T cells from naive cord blood lymphocytes

Blood ◽  
2006 ◽  
Vol 108 (5) ◽  
pp. 1770-1773 ◽  
Author(s):  
Kyung-Duk Park ◽  
Luciana Marti ◽  
Joanne Kurtzberg ◽  
Paul Szabolcs
Keyword(s):  
T Cells ◽  
Cord Blood ◽  
Cytotoxic T Cells ◽  
Transplant Recipients ◽  
Tnf Α ◽  
Donor T Cells ◽  
Specific Cytotoxicity ◽  
Cytokine Milieu ◽  
Cmv Disease

Adoptive transfer of CMV-specific cytotoxic T cells (CTLs) expanded in vitro from memory donor T cells can reduce the incidence of CMV disease in allogeneic transplant recipients. However, this approach has been unavailable in the cord blood (CB) transplantation setting because CB T cells are antigen naive and biased toward Th2/Tc2 function. We developed a protocol to in vitro prime and expand CMV-specific CTLs from CB. T cells were primed with cytokines to trigger skewing toward Th1/Tc1 lineage before encountering monocyte and CD34+ progenitor-derived dendritic cells loaded with CMV antigen and its immune complex. CMV-pulsed cultures expanded significantly more over 4 to 6 weeks than CMV cultures despite identical cytokine milieu. T cells isolated from CMV+ cultures showed a preferential expansion of CD45RA-/RO+/CD27+ T cells compared to CMV- cultures. CMV-specific IFN-γ- and TNF-α-producing CD4+ (Th1) and CD8+ (Tc1) T cells were enriched after 3 to 4 weeks and CMV-specific cytotoxicity developed 1 to 2 weeks later.

G-CSF Activated Granulocytes Inhibit Experimental Graft-versus-Host Disease.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4989-4989
Author(s):  
Zilton F.M. Vasconcelos ◽  
Julia Farache ◽  
Bruna M. Santos Grad ◽  
Tereza S. Palmeira Grad ◽  
Luis Fernando Bouzas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Cell Activity ◽  
Control Group ◽  
Low Density ◽  
Graft Versus Host ◽  
The One

Abstract Acute Graft versus host diseas (aGVHD) is a major complication of stem cell transplantation. The disease is mediated by T cells and a higher incidence/severity would be expected when higher numbers of T cells are inoculated. However, the incidence of aGVHD in PBST, which carries about 10 times more T cells then BMT, is not higher than the one found in later. This finding indicates a modulatory role for G-CSF over T cell activity. We had previously shown that T cells from G-CSF treated PBSC donors do not produce g-IFN nor IL-4 and that this inhibition was mediated by low density, G-CSF activated, granulocytes. In order to test if in fact G-CSF activated granulocytes could inhibit disease, we first checked if G-CSF could generate low density granulocytes, in vivo and in vitro. Indeed, either in vivo(21mg /day - 5 days) or in vitro (150 ng -12hs) with G-CSF generates low density granulocytes which co-purify with the mononuclear cells in the ficoll® gradient. Moreover, as we had shown in humans, these low density cells, inhibit the production of g-IFN by anti-CD3 activated T cells on flow cytometry studies (17%-T cells alone versus 3% T cells with granulocytes 1:1). Radiation quimaeras were set with (B6 X BALB/c)F1 as hosts reconstituted with T cell depleted C57Bl6 bone marrow, in the presence or absence of nylon wool selected spleen cells (NWSC), as T cell source, from normal or G-CSF treated mice. As previously shown by others, NWSC from G-CSF treated mice diminishes the incidence of acute disease on day 20 post-transplant, from 75 to 25%. In order to investigate if this inhibition was dependent on the activated granulocytes present in the NWSC from G-CSF treated mice, granulocytes were depleted with anti-GR1 and complement. In this case, the incidence of disease is the same or even higher (75% experiment#1 and 100% in experiment #2) than the one observed on the control group (NWSC from control mice). These results strongly suggest that activated granulocytes could indeed inhibit aGVHD. We then generated activated granulocytes in vitro, by treating spleen derived high density granulocytes with 150ng of G-CSF for 12 hs. After the incubation period, a new ficoll® gradient was performed and the low density cells were obtained. T cell contamination on the second gradient was eliminated by anti-CD4 and CD8 complement lysis. These activated granulocytes were inoculated together with NWSC from control mice in the radiation quimaeras at a 1:1 ratio. In this case 100% disease inhibition was observed when compared to the positive control group, where 75% of the animals got sick. Our data indicate that activated granulocytes are the major mediators of the G-CSF immunossupressive effects and that these cells can be used as a novel immune modulator in clinical transplantation to prevent acute GVHD.

PSK and Trx80 inhibit B-cell growth in EBV-infected cord blood mononuclear cells through T cells activated by the monocyte products IL-15 and IL-12

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1606-1613 ◽  
Author(s):  
Anquan Liu ◽  
Jack L. Arbiser ◽  
Arne Holmgren ◽  
George Klein ◽  
Eva Klein
Keyword(s):  
T Cells ◽  
Cord Blood ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Nk Cell ◽  
Barr Virus ◽  
Epstein Barr

AbstractEpstein-Barr virus (EBV)–specific immunologic memory is not transferred from mother to child. In vitro infection of cord blood cells can therefore readily lead to the outgrowth of transformed B lymphocytes. We found that the immunomodulator polysaccharide K (PSK) or the mitogenic cytokine truncated thioredoxin (Trx80) inhibited the EBV-induced B-cell proliferation. Using signaling lymphocytic activation molecule (SLAM)–associated protein (SAP) induction as a sign for T- and natural killer (NK) cell activation, we could follow it without any need for cell separation because neither macrophages nor B lymphocytes express SAP. The results suggest the following scenario: EBV infected and activated B lymphocytes. Upon interacting with these cells, T cells became posed for responding to cytokines produced by monocytes. Both PSK and Trx80, which is a secreted C-terminally truncated thioredoxin, activated the monocytes, which then produced cytokines in the presence of the primed T cells. PSK induced interleukin-15 (IL-15), while Trx80 induced IL-12 production. Both cytokines activated the T cells for function. Phosphatidylinositol 3–(PI 3)–kinase and reactive oxygen species (ROSs) were involved in the PSK-induced activation of monocytes. Restimulation of the cultures with EBV-transformed B cells generated specific cytotoxic activity.

scholarly journals Neutralization of Interleukin-10 from CD14+ Monocytes Enhances Gamma Interferon Production in Peripheral Blood Mononuclear Cells from Mycobacterium avium subsp. paratuberculosis-Infected Goats

2009 ◽  
Vol 16 (7) ◽  
pp. 1003-1011 ◽  
Author(s):  
Kari R. Lybeck ◽  
Anne K. Storset ◽  
Ingrid Olsen
Keyword(s):  
T Cells ◽  
Mycobacterium Avium ◽  
Mononuclear Cells ◽  
Cell Receptor ◽  
Interleukin 10 ◽  
Gamma Interferon ◽  
Regulatory Mechanisms ◽  
Interferon Production ◽  
Peripheral Blood Mononuclear

ABSTRACT The gamma interferon assay is used to identify Mycobacterium avium subsp. paratuberculosis-infected animals. It has been suggested that regulatory mechanisms could influence the sensitivity of the test when it is performed with cells from cattle and that the neutralization of interleukin-10 (IL-10) in vitro would increase the gamma interferon responses. To investigate the regulatory mechanisms affecting the gamma interferon assay with cells from goats, blood was collected from M. avium subsp. paratuberculosis-infected, M. avium subsp. paratuberculosis-exposed, and noninfected goats. Neutralization of IL-10 by a monoclonal antibody resulted in increased levels of gamma interferon production in M. avium subsp. paratuberculosis purified protein derivative (PPDj)-stimulated samples from both infected and exposed goats. However, the levels of gamma interferon release were also increased in unstimulated cells and in PPDj-stimulated cells from some noninfected animals following neutralization. Depletion of putative regulatory CD25high T cells had no clear effect on the number of gamma-interferon-producing cells. The IL-10-producing cells were identified to be mainly CD14+ major histocompatibility complex class II-positive monocytes in both PPDj-stimulated and control cultures and not regulatory T cells. However, possible regulatory CD4+ CD25+ T cells produced IL-10 in response to concanavalin A stimulation. The numbers of CD4+, CD8+, and CD8+ γδT-cell receptor-positive cells producing gamma interferon increased following IL-10 neutralization. These results provide insight into the source and the role of IL-10 in gamma interferon assays with cells from goats and suggest that IL-10 from monocytes can regulate both innate and adaptive gamma interferon production from several cell types. Although IL-10 neutralization increased the sensitivity of the gamma interferon assay, the specificity of the test could be compromised.

Analysis of the T-Cell Receptor Vα Gene Repertoire and Clonal Expansion in the Benzene-Exposed Group.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3874-3874
Author(s):  
Bo Li ◽  
Yangqiu Li ◽  
Shaohua Chen ◽  
Lijian Yang ◽  
Jiayu Chen ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Clonal Expansion ◽  
Cell Receptor ◽  
Exposed Group ◽  
Skewed Distribution ◽  
Gene Repertoire ◽  
Peripheral Blood Mononuclear ◽  
Pcr Products ◽  
Expression Rate

Abstract Benzene is a potent human leukemogen, but its mechanism of hematotoxicity is uncertain. It is well know that benzene inhibit T cells proliferation. Several reports revealed that clonal expansion TCR Vβ T cells could be found in workers exposed to benzene. In this study we observe the distribution of TCR Vα gene repertoire and clonal expansion in peripheral blood mononuclear cells from 9 donors and 16 workers exposed to benzene. Complementarity determining region 3 (CDR3) of TCR Vα subfamily genes were amplified using RT-PCR. The PCR products were further analyzed by genescan to evaluating clonality of T cells. 29 Vα subfamily could be detected in 9 donors.1~11 Vα subfamilies were identified in all but one of the workers studied. The most frequently expressed Vα subfamily were Vα3, Vα12 and Vα19 (68.8%), Vα14(56.3%), with a lower expression rate found in Vα5,Vα15, Vα16, Vα 22, Vα 23 and Vα 24 (6.3%). Clonal expansion T cells in one or more Vα subfamily were found in 12 out of all workers studied, including oligoclonal, oligocolonal trend and bioclonal patterns. The frequency of clonal expansion T cells in Vα12, Vα14 and Vα19 subfamilies were higher than others. In conclusion, skewed distribution and clonal expansion of TCR Vα subfamily T cells could be found in workers exposed to benzene. Vα12, Vα14 and Vα19 subfamilies may be highly sensitive to benzene exposed. This is the first report of clonal expansion TCR Vα T cells in the benzene-exposed group. The bias pattern of TCR Vα T cells may be due to the immune cytotocicity from benzene. However, whether the oligoclonality in some Vα subfamilies reflect the phenomenon of clone absense or may be a response clone to benzene-related impairment during exposed to benzene, remains an open question.

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