TCRzeta Expression Research Articles

Measuring the T-cell down-regulation of TCR-zeta, ZAP-70 and CD28 in arthritis patients: An old tool for new biomarkers.

Low T-cell receptor (TCR)/CD28 signaling lymphocytes are expanded in arthritis. We asked whether the down-expression of TCR-related molecules correlates with specific arthritis characteristics and if it has clinical implications. TCR-ZETA, ZAP-70 and CD28 expression was measured by flow cytometry in synovial fluid (SF) and peripheral blood (PB)-derived T cells. In PB, ZETA-downregulation in CD4+ CD28+ and consequent CD4+ CD28lowZETAlow cell expansion correlate with CRP elevation, leukocyte recruitment into SF and, primarily, disease activity (DAS). In some patients, ZETA-downregulation extends to CD8+ CD28null and/or CD8+ CD28+ cells, and this correlates with enhanced leukocyte recruitment, multiple joint involvement, and disability index (HAQ). ZETA-downregulation in CD4+ CD28+ may also lead to CD4+ CD28+ ZETAnull cell expansion, which strongly correlates with HAQ. In SF, ZETA-downregulation in CD8+ CD28null and consequent CD8+ CD28nullZETAlow/null cell expansion correlate with CRP elevation and neutrophilic influx into SF, whereas ZAP-downregulation in CD8+ CD28+ and consequent CD8+ CD28lowZAPlow cell expansion strongly correlate with HAQ and DAS. ZETA-downregulation is preponderant in SF of seronegative arthritides, with seronegative rheumatoid arthritis showing significant down-regulation in CD8+ CD28null, and non-rheumatoid arthritides showing significant down-regulation in CD4+ CD28+ . Altogether, we identified new molecular and cellular biomarkers of arthritis-related T-cell inflammation, useful for assessing arthritis activity, predicting polyarticular progression and functional impairment, characterizing seronegative arthritides, and possibly tailoring immunotherapies.

Increasing TCR Zeta Expression and Maintaining the Clonality of T Cells from AML Patients after IL-2, IL-7 and IL-12 Induction

T-cell immunodeficiency is a common feature in patients with leukemia, lower activation of T cells was one of reasons. The TCR zeta chain has emerged as a key subunit of the T-cell antigen receptor, which plays a central role in the signal-transducing events leading to T cell activation. The proliferation and activation of T cells may be inducted by T cell related cytokines. In this study, we explored the change of TCR zeta gene expression and the clonality of T cells after induction with different immune cytokines, including IL-2, IL-7 or IL-12. CD3+ T cells sorted from peripheral blood of 4 cases with AML were induced with different immune cytokines, including IL-2, IL-7, IL-12, anti-CD3 and anti-CD28 antibodies in vitro. The expression levels of TCR zeta gene and related genes in T cells before and after induction were then analyzed by fluorescence quantitative RT-PCR. The distribution and clonality of TCR Vβ subfamily T cells were analyzed by RT-PCR and Genescan techniques. Increasing expression levels of TCR zeta gene and zap-70 (TCR zeta chain associated-protein) gene in CD3+T cells from AML patients were found after induction with single stimulating factor or the combination with different cytokines, while the expression of FcεRIγ (TCR ζ gene complementary factor) was down-regulated. We further compared the T cell clonality in CD3+T cells from AML patients after cytokine induction, eight to 22 TCR V β subfamilies could be detected in T cells from AML cases, most of them displayed polyclonal expansion. The number of expressed TCR Vβ subfamilies was increased without the change of clonality in T cells induced by CD3+CD28+IL7. In conclusion, TCR zeta gene and its related genes could be upregulated through induction with different cytokine combination such as IL-2, IL-7 and IL-12, therefore to improve the T cell activation in patients with AML. And the main effect of cytokines might to maintain the T cell clonality and nonspecific amplification of T cell clones. Further investigation can be designed to amplify the specific anti-AML TCR Vβ clones using AML associated antigens and such cytokine combination. DisclosuresShi:National Natural Science Foundation of China (no. 81100353, 81270604), the Fundamental Research Funds for the Central Universities (No. 21611447, 21612116), And Medical Science Foundation of Guangdong Province(A2011325). : Research Funding.

Does sustained downregulation of the TCRzeta chain define the transition from antigen mode to inflammation mode in effector T lymphocytes?

The molecular events that define the early phase of activation and differentiation of effector T cells have been well characterized. Those events promoting the effector function of chronically activated T cells at sites of inflammation are less well understood. Using in vitro and in vivo models, we have explored the effects of the chronic inflammatory process on T-cell differentiation by studying the effects of tumor necrosis factor (TNF) on T-cell activation and effector responses. These studies have revealed that TNF-stimulated T cells resemble rheumatoid arthritis synovial T cells since they express cell surface activation antigens, but are profoundly hyporesponsive to T-cell receptor (TCR) engagement. This may be explained, at least in part, by the observation that TNF selectively targets the expression of the TCRzeta chain. Loss of TCRzeta expression perturbs the assembly, expression and stability of the TCR/CD3 complex, leading to attenuation of membrane proximal tyrosine phosphorylation, intracellular calcium mobilisation and the transcription of cytokine genes upon TCR engagement, when compared with untreated T cells. We set out to explore whether TCRzeta expression could be used to identify chronically activated, hyporesponsive T cells in vivo. Using a FACS-based assay, we have identified subsets of CD3+ T cells expressing low levels of TCRzeta (hereafter termed TCRzetadim cells) in the peripheral blood of healthy donors, as well as patients with inflammatory arthritis. Subsequent experiments revealed that, when compared with TCRzetabright cells, the TCRzetadim population is enriched for cells expressing effector memory cell surface markers. By staining with HLA class I/peptide tetramer complexes, CD8+TCR-zetadim cells are enriched for antigen-specific T cells after stimulation in vitro with specific peptide. While TCRzetadim cells are hyporesponsive to TCR engagement, they retain effector potential, since a significant proportion are TNF-α and IFN-γ producers upon stimulation with phorbol ester and calcium ionophore. In contrast, fewer produce IL-10 when compared with the TCRzetabright subset. These data suggest that TCRzetadim T cells, which are abundant at sites of inflammation, may represent a subset of circulating antigen experienced effector memory cells. Sustained downregulation of TCRzeta may define a checkpoint where the intracellular signals driving T-cell differentiation switch from antigen mode to inflammation mode.

CD2 and CD3 receptor-mediated tolerance: constraints on T cell activation.

Antigen specific allograft tolerance is induced in mice by anti-CD2 plus anti-CD3epsilon monoclonal antibody (mAb) treatment. Because anti-CD2 mAb inhibits several aspects of anti-CD3epsilon driven T cell activation, we investigated what components of T cell activation are required or may be dispensed with for tolerance induction. Anti-CD3epsilon-mediated T cell activation depends on FcgammaR interactions. To assess the role of FcgammaR-mediated T cell activation in tolerance induction, FcgammaR binding IgG or non-binding IgG3 anti-CD3epsilon mAbs were examined. These mAbs, administered in conjunction with anti-CD2, were equally effective in inducing tolerance. Moreover, in vivo administration of a blocking mAb directed against the FcgammaR, or the use of allograft recipients deficient in FcgammaR, had no effect on tolerance induction. Blocking IL-2 using mAb directed against IL-2 or IL-2R also did not prevent the induction of tolerance. These results suggest that complete T cell activation was not required for tolerance induction. However, substitution of a partially activating mAb, directed against the T cell receptor (TCR) beta subunit for anti-CD3epsilon, failed to synergize with anti-CD2 mAb to induce tolerance. The anti-TCRbeta mAb and anti-CD3epsilon mAb were found to differentially down modulate expression of TCR/CD3 complex subunits. In particular, anti-CD3epsilon caused transient down modulation of the TCRbeta receptor subunit and the TCRzeta signaling module, and this pattern was enhanced and prolonged by anti-CD2. Anti-TCRbeta caused persistent TCRzeta modulation but no TCRbeta modulation, and anti-CD2 did not influence this pattern. These results suggest that, although full T cell activation is not required for the induction of tolerance by anti-CD2 plus anti-CD3epsilon mAb, a signal transduction pathway that is associated with TCRbeta and TCRzeta expression, and, specifically, is perturbed by mAb binding of the CD3epsilon epitope, is critical.

CD3 hyporesponsiveness and in vitro apoptosis are features of T cells from both malignant and nonmalignant secondary lymphoid organs.

There is a dogma in tumor immunology that tumor-infiltrating lymphocytes (TIL) are defective based on their lack of antitumoral efficacy in vivo and on impaired response to in vitro functional tests. However, TIL have been compared usually with peripheral blood T lymphocytes, raising doubts on the conclusions drawn. Therefore, we compared TIL from B cell non-Hodgkin's lymphomas (NHL) with T cells from nonmalignant secondary lymphoid organs. NHL-TIL were unresponsive to activation by immobilized anti-CD3 mAb, although bypassing T cell receptor (TCR)/CD3 signaling led to proliferation. The poor proliferative responses of NHL-TIL could not be explained by quantitative defects in TCRzeta expression. NHL-TIL underwent marked spontaneous apoptosis in vitro with loss of approximately 50% of cells after 24 h of culture. This was associated with downregulation of the antiapoptotic Bcl-xL and Bcl-2 proteins, whereas viable NHL-TIL maintained their expression. IL-2, anti-CD3/IL-2, and manipulation of the Fas/Fas-ligand death pathway had no effect on NHL-TIL survival. Apoptosis was not due to increased cell cycling, as NHL-TIL were quiescent, nonproliferating cells. T cells from inflammatory, nonmalignant tissues gave similar functional results to NHL-TIL, suggesting the existence of factors common to the microenvironment of these diverse pathologies. Thus, the quiescent, anergic phenotype of NHL-TIL cannot be attributed solely to tumor factors, but rather is a feature of T cells from chronic inflammatory lesions.

Expression of signal transducing T-cell receptor zeta molecules after adoptive immunotherapy in patients with gastric and colon cancer.

We and others have shown decreased expression of T-cell receptor-CD3-associated signal transducing zeta molecules (TCRzeta) in tumor infiltrating and peripheral T cells of patients with advanced cancer. In the present study, we performed adoptive immunotherapy (AIT) with tumor-associated lymphocytes (TAL) in patients with gastric (n = 11) and colon (n = 3) cancer with stage IV and investigated whether the alteration of signal transducing molecules was observed with AIT, compared to an untreated control group (n = 13). Autologous TALs isolated from malignant ascites or pleural effusion were cultured with stimulation of autologous tumor in the presence of interleukin-2 (IL-2) and were transferred to the patients. TCR zeta expression in peripheral T cells was measured by flow cytometric analysis of permeabilized cells with anti-zeta monoclonal antibody (MAb) (TIA-2) before and after AIT. We confirmed the down-regulation of TCR zeta expression in peripheral blood lymphocytes (PBL) of patients with gastric and colon cancer with stage IV compared to healthy donors (n = 15). AIT induced up-regulation of TCR zeta expression in 2 of 14 treated patients, caused no significant change of TCR zeta expression in 7 patients and induced further down-regulation in 5 patients. The patients who achieved clinical responses (n = 3) with AIT showed no significant change of TCR zeta expression. On the other hand, in the control group without adoptive transfer, further down-regulation of TCR zeta expression was observed during the corresponding periods, paralleling disease progression. Taken together, TCR zeta expression in the patients was further down-regulated, corresponding to disease progression in individual cancer patients. In some patients, AIT could induce increased or stable TCR zeta expression. The quantitative analysis of TCR zeta expression might provide vital information that can be used to optimize therapy by preserving immune functions within cancer patients.

PBLs of early breast carcinoma patients with a high nuclear grade tumor unlike PBLs of cervical carcinoma patients do not show a decreased TCR zeta expression but are functionally impaired.

Peripheral blood lymphocytes (PBLs) of patients with cervical intraepithelial neoplasia (CIN), cervical carcinoma, or early breast carcinoma were tested for the expression of T cell receptor zeta chain (TCR zeta) and CD16 zeta chain and production of interferon-gamma (IFN gamma) and interleukin (IL) 10. We found that in all patients with CIN and invasive cervical carcinoma, PBLs showed a reduced TCR zeta and CD16 zeta expression and a significant down-regulation in IFN gamma production (a T helper 1 cytokine) after anti-CD3 stimulation. However, the IL 10 secretion (a T helper 2 cytokine) was not diminished after anti-CD3 stimulation. This indicates that only T helper 1 cells are affected by the down-regulation of the TCR zeta chain expression. We also analyzed PBLs of 12 patients with early breast carcinoma. In these patients, we found TCR zeta and CD16 zeta expression down-regulation in 2 of 12 patients. Six of 12 patients had an enhanced TCR zeta expression. The enhanced TCR zeta expression correlated with a reduced IFN gamma expression after anti-CD3 stimulation. These data show that in general PBLs of early breast carcinoma patients, unlike those of cervical carcinoma patients, do not show a decreased TCR zeta expression. However, a functional impairment of T cells was observed in the subgroup of early breast carcinoma patients with a high nuclear grade of their tumor.

Altered pattern of TCR/CD3-mediated protein-tyrosyl phosphorylation in T cells from patients with systemic lupus erythematosus. Deficient expression of the T cell receptor zeta chain.

Cellular immunity aberrations in patients with SLE are underscored by the abnormal early Ag receptor-mediated lymphocyte signal transduction pathway. To further characterize the T cell receptor (TCR)/CD3-initiated signaling defects, we studied 22 patients with SLE, 12 patients with other systemic rheumatic diseases, and 14 normal donors. The early (1 min) TCR/CD3-mediated tyrosine phosphorylation of cellular proteins with a molecular size between 36 and 64 kD was increased in 15 of 21 SLE patients, compared to normal or disease control subjects. The deficiency or absence of a band with a molecular size of approximately 16 kD in the immunoblots of SLE patients led us to investigate the expression of the TCRzeta chain. In immunoblots using anti-zeta antibodies we found that 10 of 22 lupus patients tested lacked the expression of TCRzeta, which was always present in control subjects (P < 0.001). Flow cytometric studies using permeabilized cells confirmed the deficiency or absence of the TCRzeta chain in lupus T cells. Using Northern blots we found that for eight patients tested, the TCRzeta mRNA was missing in three, decreased in three, and apparently normal in two patients (P < 0.003), but was always present in control subjects. Reverse transcriptase-PCR verified Northern blot results. We conclude that TCRzeta chain expression is either decreased or absent in the majority of patients with SLE, but not in patients with other systemic rheumatic diseases, regardless of disease activity, treatment status, or clinical manifestations. The previously described increases in TCR-initiated Ca2+ responses and the herein described increases in TCR-induced protein tyrosine phosphorylation and deficient TCRzeta expression may represent intrinsic defects modulating lupus T cell function.