α1β1 Integrin+ and Regulatory Foxp3+ T Cells Constitute Two Functionally Distinct Human CD4+ T Cell Subsets Oppositely Modulated by TNFα Blockade

Formation and phenotypic characterization of CD49a, CD49b and CD103 expressing CD8 T cell populations in human metastatic melanoma

Integrins α1β1 (CD49a), α2β1 (CD49b) and αEβ7 (CD103) mediate retention of lymphocytes in peripheral tissues, and their expression is upregulated on tumor infiltrating lymphocytes (TIL) compared to circulating lymphocytes. Little is known about what induces expression of these retention integrins (RI) nor whether RI define subsets in the tumor microenvironment (TME) with a specific phenotype. Human metastatic melanoma-derived CD8 TIL could be grouped into five subpopulations based on RI expression patterns: RI^neg, CD49a⁺ only, CD49a⁺CD49b⁺, CD49a⁺CD103⁺, or positive for all three RI. A significantly larger fraction of the CD49a⁺ only subpopulation expressed multiple effector cytokines, whereas CD49a⁺CD103⁺ and CD49a⁺CD49b⁺ cells expressed IFNγ only. RI^neg and CD49a⁺CD49b⁺CD103⁺ CD8 TIL subsets expressed significantly less effector cytokines overall. Interestingly, however, CD49a⁺CD49b⁺CD103⁺ CD8 expressed lowest CD127, and highest levels of perforin and exhaustion markers PD-1 and Tim3, suggesting selective exhaustion rather than conversion to memory. To gain insight into RI expression induction, normal donor PBMC were cultured with T cell receptor (TCR) stimulation and/or cytokines. TCR stimulation alone induced two RI⁺ cell populations: CD49a single positive and CD49a⁺CD49b⁺ cells. TNFα and IL-2 each were capable of inducing these populations. Addition of TGFβ to TCR stimulation generated two additional populations; CD49a⁺CD49b^negCD103⁺ and CD49a⁺CD49b⁺CD103^+. Taken together, our findings identify opportunities to modulate RI expression in the TME by cytokine therapies and to generate subsets with a specific RI repertoire in the interest of augmenting immune therapies for cancer or for modulating other immune-related diseases such as autoimmune diseases.

Pathway analysis to identify genetic variants associated with efficacy of adalimumab in rheumatoid arthritis

AIM

About 30% of rheumatoid arthritis patients have no clinical benefit from TNF inhibitors. Genome-wide association (GWA) and candidate gene studies tested several putative genetic variants for TNF inhibitor efficacy with inconclusive results. Therefore, this study applied a systematic pathway analysis.

PATIENTS & METHODS

A total of 325 rheumatoid arthritis patients treated with adalimumab were genotyped for 223 SNPs. We tested the association between SNPs and European League Against Rheumatism response and remission at 14 weeks under the additive genetic model using logistic regression.

RESULTS

A total of 3 SNPs located in CD40LG (rs1126535), TANK (rs1267067) and VEGFA (rs25648) showed association with both end points. TNFAIP3 (rs2230926) had the strongest effect related to European League Against Rheumatism response.

CONCLUSION

This exploratory study suggests that TNFAIP3, CD40LG, TANK and VEGFA play a role in the response to adalimumab treatment.

IL-10/IFNγ co-expressing CD4(+) T cells induced by IL-10 DC display a regulatory gene profile and downmodulate T cell responses

Induced regulatory T cells (iTreg) are imperative for tolerance induction and spreading of infectious tolerance. Ex vivo generated tolerogenic dendritic cells (tDCs) have strong therapeutic potential to induce antigen-specific iTreg. We previously demonstrated that IL-10 tDC-primed T cells are very suppressive and produce IL-10. Here, we show that the majority of IL-10(+) T cells co-express IFNγ, giving rise to the question whether these cells are proinflammatory or regulatory. Whole genome gene expression analysis revealed a strong regulatory gene profile and a suppressed Th1 gene profile for IL-10/IFNγ co-expressing CD4(+) T cells. Protein analysis confirmed an extensive regulatory phenotype for IL-10(+)/IFNγ(+) T cells, with specific enhanced expression of GARP and PD-1. In line with these data, isolated IL-10(+)/IFNγ(+) T cells displayed potent suppressive capacity. Thus, IL-10/IFNγ co-expressing CD4(+) T cells induced by IL-10 tDC show dominance of immunomodulation over Th1-mediated immunoactivation and can contribute to induction or spreading of immunological tolerance.

T Cell Migration in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation in joints, associated with synovial hyperplasia and with bone and cartilage destruction. Although the primacy of T cell-related events early in the disease continues to be debated, there is strong evidence that autoantigen recognition by specific T cells is crucial to the pathophysiology of rheumatoid synovitis. In addition, T cells are key components of the immune cell infiltrate detected in the joints of RA patients. Initial analysis of the cytokines released into the synovial membrane showed an imbalance, with a predominance of proinflammatory mediators, indicating a deleterious effect of Th1 T cells. There is nonetheless evidence that Th17 cells also play an important role in RA. T cells migrate from the bloodstream to the synovial tissue via their interactions with the endothelial cells that line synovial postcapillary venules. At this stage, selectins, integrins, and chemokines have a central role in blood cell invasion of synovial tissue, and therefore in the intensity of the inflammatory response. In this review, we will focus on the mechanisms involved in T cell attraction to the joint, the proteins involved in their extravasation from blood vessels, and the signaling pathways activated. Knowledge of these processes will lead to a better understanding of the mechanism by which the systemic immune response causes local joint disorders and will help to provide a molecular basis for therapeutic strategies.

CD49a promotes T-cell-mediated hepatitis by driving T helper 1 cytokine and interleukin-17 production

It is becoming increasingly clear that the T-cell-mediated immune response is important in many diseases. In this study, we used concanavalin A (Con A) -induced hepatitis to investigate the role of CD49a in the molecular and cellular mechanism of the T-cell-mediated immune response. We found that CD49a(-/-) mice had significantly reduced levels of serum alanine aminotransferase and were protected from Con A-induced hepatitis. CD49a deficiency led to decreased production of interferon-γ (IFN-γ) and interleukin-17A (IL-17A) after Con A injection. Furthermore, we found that hepatic CD4(+) T cells and invariant natural killer T cells up-regulated CD49a expression, along with enhanced activation after Con A injection, leading to production of inflammatory cytokines by these T cells. Blockade of CD49a in vivo ameliorated Con A-induced hepatitis with reduced production of IFN-γ and IL-17A. Hence, CD49a promoted Con A-induced hepatitis through enhancing inflammatory cytokine production (IFN-γ and IL-17A) by CD4(+) T and invariant natural killer T cells. The protective effect of CD49a blockade antibody suggested a new target therapeutic molecule for intervention of T-cell-mediated liver injury.

Inhibition of TNF receptor signaling by anti-TNFα biologicals primes naïve CD4(+) T cells towards IL-10(+) T cells with a regulatory phenotype and function

TNFα is a potent pro-inflammatory cytokine playing a pivotal role in several autoimmune diseases. Little is known about the mechanism of TNFα blocking agents on naïve T cell differentiation. Here, we report that neutralizing TNFα during priming of naïve CD4(+) T cells by dendritic cells favors development of IL-10(+) T helper cells. TNFα counteracts IL-10(+) T cell priming mainly via TNFRI receptor signaling. While initial T cell activation was not affected, neutralization of TNFα negatively affected sustained T cell differentiation in later stages of T cell priming. Whole genome gene expression analysis revealed an extended regulatory gene profile for anti-TNFα-treated T cells. Indeed, neutralizing TNFα during naïve T cell priming enhanced the suppressive function of anti-TNFα-treated T cells. Taken together, inhibition of TNFα-TNFR interaction shifts the balance of Th cell differentiation towards IL-10 expressing suppressive T cells, which may be one of the beneficial mechanisms in TNFα blocking therapies.

Anti-tumor necrosis factor α targets protein kinase B/c-Akt-induced resistance of effector cells to suppression in juvenile idiopathic arthritis

OBJECTIVE

To determine whether therapeutic strategies that block interleukin-6 (IL-6) or tumor necrosis factor α (TNFα) can improve the responsiveness of Teff cells to suppression in patients with juvenile idiopathic arthritis (JIA).

METHODS

Synovial fluid mononuclear cells (SFMCs) from the inflamed joints of patients with JIA were cultured in the presence of etanercept or anti-IL-6 in vitro, and protein kinase B (PKB)/c-Akt activation and responsiveness to suppression were measured. In addition, the in vivo effects of TNFα blockade were investigated using peripheral blood mononuclear cells obtained from patients before and after the start of etanercept therapy.

RESULTS

In vitro treatment of SFMCs with anti-IL-6 led to improved Treg cell-mediated suppression of cell proliferation in some but not all patients. Blocking TNFα with etanercept, however, clearly enhanced suppression, especially that of CD8+ T cells. In the presence of etanercept, PKB/c-Akt activation of Teff cells was reduced, and cells became more susceptible to transforming growth factor β-mediated suppression, indicating that anti-TNFα directly targets resistant Teff cells.

CONCLUSION

This study is the first to show that anti-TNFα targets the resistance of Teff cells to suppression, resulting in improved regulation of inflammatory effector cells.

Integrin α1β1

Integrin α1β1 is widely expressed in mesenchyme and the immune system, as well as a minority of epithelial tissues. Signaling through α1 contributes to the regulation of extracellular matrix composition, in addition to supplying in some tissues a proliferative and survival signal that appears to be unique among the collagen binding integrins. α1 provides a tissue retention function for cells of the immune system including monocytes and T cells, where it also contributes to their long-term survival, providing for peripheral T cell memory, and contributing to diseases of autoimmunity. The viability of α1 null mice, as well as the generation of therapeutic monoclonal antibodies against this molecule, have enabled studies of the role of α1 in a wide range of pathophysiological circumstances. The immune functions of α1 make it a rational therapeutic target.

Selective blockade of tumor necrosis factor receptor I inhibits proinflammatory cytokine and chemokine production in human rheumatoid arthritis synovial membrane cell cultures

OBJECTIVE

To determine whether selective blockade of tumor necrosis factor receptor I (TNFRI) affects spontaneous proinflammatory cytokine and chemokine production in ex vivo-cultured human rheumatoid arthritis synovial membrane mononuclear cells (MNCs) and to compare this response to that of TNF ligand blockade using etanercept.

METHODS

A bispecific, single variable-domain antibody (anti-TNFRI moiety plus an albumin binding moiety [TNFRI-AlbudAb]) was used to selectively block TNFRI. Inhibition of TNFα-mediated responses in cell lines expressing TNFRI/II confirmed TNFRI-AlbudAb potency, human rhabdomyosarcoma cell line KYM-1D4 cytotoxicity, and human umbilical vein endothelial cell (HUVEC) vascular cell adhesion molecule 1 (VCAM-1) upregulation. Eighteen RA synovial membrane MNC suspensions were cultured for 2 days or 5 days, either alone or in the presence of TNFRI-AlbudAb, control-AlbudAb, or etanercept. Proinflammatory cytokines and chemokines in culture supernatants were measured by enzyme-linked immunosorbent assays. A mixed-effects statistical analysis model was used to assess the extent of TNFRI selective blockade, where the results were expressed as the percentage change with 95% confidence intervals (95% CIs).

RESULTS

TNFRI-AlbudAb inhibited TNFα-induced KYM-1D4 cell cytotoxicity (50% inhibition concentration [IC50 ] 4 nM) and HUVEC VCAM-1 up-regulation (IC50 12 nM) in a dose-dependent manner. In ex vivo-cultured RA synovial membrane MNCs, selective blockade of TNFRI inhibited the production of proinflammatory cytokines and chemokines to levels similar to those obtained with TNF ligand blockade, without inducing cellular toxicity. Changes in cytokine levels were as follows: -23.5% (95% CI -12.4, -33.2 [P = 0.004]) for granulocyte-macrophage colony-stimulating factor, -33.4% (95% CI -20.6, -44.2 [P ≤ 0.0001]) for interleukin-10 (IL-10), -17.6% (95% CI 3.2, -34.2 [P = 0.0880]) for IL-1β, and -19.0% (95% CI -3.4, -32.1 [P = 0.0207]) for IL-6. Changes in chemokine levels were as follows: -34.2% (-14.4, -49.4 [P = 0.0030]) for IL-8, -56.6% (-30.7, -72.9 [P = 0.0011]) for RANTES, and -24.9% (2, -44.8 [P = 0.0656]) for monocyte chemotactic protein 1.

CONCLUSION

In ex vivo-cultured RA synovial membrane MNCs, although a limited role of TNFRII cannot be ruled out, TNFRI signaling was found to be the dominant pathway leading to proinflammatory cytokine and chemokine production. Thus, selective blockade of TNFRI could potentially be therapeutically beneficial over TNF ligand blockade by retaining the beneficial TNFRII signaling.

Infliximab inhibits activation and effector functions of peripheral blood T cells in vitro from patients with clinically active ulcerative colitis

Many patients with inflammatory bowel disease (IBD) are undergoing therapy with infliximab, an antibody specific for TNF. However, the exact mechanisms of action of infliximab are not completely understood. The aim of this study was to determine the in vitro effects of infliximab on blood T cells derived from anti-TNF therapy-naïve ulcerative colitis (UC) patients with clinically active disease. Peripheral blood mononuclear cells were stimulated polyclonally or by antigen in the presence or absence of infliximab. The T cell phenotype was investigated by flow cytometry, cytokine secretion was determined by ELISA, and cell proliferation was determined by thymidine assay or CFSE dye. Presence of infliximab resulted in reduced expression of CD25 in CD4(+) and CD8(+) T cell populations and inhibited secretion of IFN-γ, IL-13, IL-17A, TNF as well as granzyme A. Infliximab also suppressed CD4(+) and CD8(+) T cell proliferation. These effects of infliximab were recorded both in T cells activated by polyclonal and antigen-specific stimulation. The effects of infliximab on T cell apoptosis and induction of FOXP3(+) CD4(+) T regulatory cells were ambiguous and depended on the originating cellular source and/or the stimulation mode and strength. In conclusion, infliximab is able to reduce T cell activation as measured by CD25, proliferation and cytokine secretion in vitro from UC patients with clinically active disease. These data suggest that suppression of T cell activity may be important for infliximab-mediated disease remission in patients with UC.

The effect of autoimmune arthritis treatment strategies on regulatory T-cell dynamics

PURPOSE OF REVIEW

Since their discovery over 15 years ago, intensive research has focused on the presence, phenotype and function of FOXP3(+) regulatory T cells (Treg) in autoimmune diseases such as rheumatoid arthritis (RA). The questions of whether Treg deficiencies underlie autoimmune pathology and whether or how Treg-related therapeutic approaches might be successful are still a subject of a vivid debate. In this review we give an overview of how current therapies influence Treg numbers and function in RA and juvenile idiopathic arthritis (JIA) and discuss these findings in the light of new Treg-based intervention strategies for autoimmune arthritis.

RECENT FINDINGS

The attempt to relate rheumatic diseases like rheumatoid arthritis and juvenile idiopathic arthritis to Treg has led to somewhat heterogeneous observations. So far, no clear defects in Treg numbers or function have been identified in autoimmune arthritis. The current standard therapies, that is methotrexate and biologicals, are generally effective, but the exact mechanism of action and their effect on Treg is not fully known. Nevertheless, the majority of in-vitro and ex-vivo data point towards a positive influence of these treatments on Treg number and function. These observations are not all consistent, however, and it is not known whether the observed effects on Treg are primary or secondary effects. To safely conduct targeted regulatory T-cell therapy in rheumatic diseases more knowledge about regulatory T-cell function in an inflammatory environment is needed that coincides with the initiative to elucidate the exact mechanism of current therapies.

T cells out of control--impaired immune regulation in the inflamed joint

Since the discovery of FOXP3+ regulatory T (T(REG)) cells over 15 years ago, intensive research has focused on their presence, phenotype and function in autoimmune disease. Whether deficiencies in T(REG) cells underlie autoimmune pathology and whether, or how, therapeutic approaches based on these cells might be successful is still the subject of debate. The potential role of T(REG)-cell extrinsic factors, such as proinflammatory cytokines and resistance of effector T cells to suppression, as the cause of regulatory defects in chronic autoimmune inflammation is an intensive area of research. It is now clear that, at the site of inflammation, antigen presenting cells (APCs) and proinflammatory cytokines drive effector T cell skewing and plasticity, and that these T cells can become unresponsive to regulation. In addition, expansion and function of T(REG) cells is affected by the inflammatory environment; indeed, new data suggest that, in certain conditions, T(REG) cells promote inflammation. This Review summarizes the latest findings on changes in effector T cell homeostasis in autoimmune disease and focuses on how mechanisms that normally regulate these cells are affected in the inflamed joints of patients with arthritis. These findings have important clinical implications and will affect the development of new therapeutic strategies for autoimmune arthritis.

γδT cells in Juvenile Idiopathic Arthritis: Higher Percentages of Synovial Vδ1+ and Vγ9+ T Cell Subsets Are Associated with Milder Disease

Objective.

To analyze γδT cell subsets in peripheral blood (PB) and synovial fluid (SF) of patients with juvenile idiopathic arthritis (JIA), and to correlate γδT cell subsets with clinical characteristics.

Methods.

γδT cell subsets as percentages of CD3+ T cells in samples of PB (n = 25) and SF (n = 93) were analyzed by flow cytometry in 93 JIA patients. The percentage of Vγ9+ γδT cells after 10 days of in vitro expansion with either interleukin 2 (IL-2) or isopentenyl pyrophosphate (IPP) plus IL-2 was determined.

Results.

Both Vδ1+ and Vγ9+ γδT cell subsets were detected in SF of all patients, but only the percentage of Vδ1+ cells was higher in SF compared to PB (p < 0.01). The distribution of γδT cell subsets was similar in different JIA subgroups, whereas antinuclear antibody (ANA)-positive patients had a higher percentage of SF Vδ1+ T cells than ANA-negative patients (p < 0.01). The percentage of SF Vδ1+ T cells was inversely associated with age at onset, recurrence of synovitis, and erythrocyte sedimentation rate; and that of SF Vγ9+ T cells was inversely correlated with age at onset and was higher in patients who recovered from disease (n = 15). IPP-induced expansion of SF Vγ9+ T cells correlated with disease remission, whereas the expansion of SF Vγ9+ T cells in media with IL-2 alone was significantly greater in patients with uveitis.

Conclusion.

The percentage of Vδ1+ and Vγ9+ γδT cells among the SF T cells and their ability to respond to IPP or IL-2 correlated with specific outcomes of JIA, suggesting their role in the immunopathogenesis of this disease.

Immune response in ovarian cancer: how is the immune system involved in prognosis and therapy: potential for treatment utilization

Ovarian cancer is one of the leading causes of cancer-related death among women. Resistance to the disease occurs in more than 70% of the cases even after treated with chemotherapy agents such as paclitaxel- and platinum-based agents. The immune system is increasingly becoming a target for intense research in order to study the host's immune response against ovarian cancer. T cell populations, including NK T cells and Tregs, and cytokines have been associated with disease outcome, indicating their increasing clinical significance, having been associated with prognosis and as markers of disease progress, respectively. Harnessing the immune system capacity in order to induce antitumor response remains a major challenge. This paper examines the recent developments in our understanding of the mechanisms of development of the immune response in ovarian cancer as well as its prognostic significance and the existing experience in clinical studies.

Trans-SILAC: sorting out the non-cell-autonomous proteome

Non-cell-autonomous proteins are incorporated into cells that form tight contacts or are invaded by bacteria, but identifying the full repertoire of transferred proteins has been a challenge. Here we introduce a quantitative proteomics approach to sort out non-cell-autonomous proteins synthesized by other cells or intracellular pathogens. Our approach combines stable-isotope labeling of amino acids in cell culture (SILAC), high-purity cell sorting and bioinformatics analysis to identify the repertoire of relevant non-cell-autonomous proteins. This 'trans-SILAC' method allowed us to discover many proteins transferred from human B to natural killer cells and to measure biosynthesis rates of Salmonella enterica proteins in infected human cells. Trans-SILAC should be a useful method to examine protein exchange between different cells of multicellular organisms or pathogen and host.

Identification of a unique population of tissue-memory CD4+ T cells in the airways after influenza infection that is dependent on the integrin VLA-1

During the immune response to influenza infection, activated T cells are distributed to both lymphoid and extralymphoid tissues, including the infected airways where direct recognition of viral Ag-bearing cells takes place. The collagen-binding alpha(1)beta(1) integrin VLA-1 is essential for the development of memory CD8(+) T cells in the airways, and although expressed by some CD4(+) T cells, its significance has not been demonstrated. We investigated the role of VLA-1 on virus-specific CD4(+) T cells during and after primary or secondary influenza infection of mice. The proportion of CD4(+) cells expressing CD49a (alpha(1) integrin) was low in all tissues sampled during primary infection but increased in the airways after viral clearance. Furthermore, during the first 24 h of a secondary influenza challenge, the majority of IFN-gamma-secreting effector CD4(+) T cells from the airways was in the CD49a(+) population. Airway CD49a(+)CD4(+) cells also expressed reduced markers of apoptosis compared with CD49a(-) cells, and fewer memory or effector CD4(+) cells could be recovered from airways of alpha(1)(-/-) mice, although lymphoid tissues appeared unaffected. These data suggest VLA-1 expression defines a population of tissue memory CD4(+) T cells that act as rapid effectors upon reinfection, and VLA-1 expression is integral to their accumulation in the airways.

Reduced intensity conditioning for allogeneic hematopoietic stem-cell transplant determines the kinetics of acute graft-versus-host disease

BACKGROUND

Preparative myeloablative conditioning regimens for allogeneic hematopoietic stem-cell transplantation (HSCT) may control malignancy and facilitate engraftment but also contribute to transplant related mortality, cytokine release, and acute graft-versus-host disease (GVHD). Reduced intensity conditioning (RIC) regimens have decreased transplant related mortality but the incidence of acute GVHD, while delayed, remains unchanged. There are currently no in vivo allogeneic models of RIC HSCT, limiting studies into the mechanism behind RIC-associated GVHD.

METHODS

We developed two RIC HSCT models that result in delayed onset GVHD (major histocompatibility complex mismatched (UBI-GFP/BL6 [H-2]-->BALB/c [H-2]) and major histocompatibility complex matched, minor histocompatibility mismatched (UBI-GFP/BL6 [H-2]-->BALB.B [H-2])) enabling the effect of RIC on chimerism, dendritic cell (DC) chimerism, and GVHD to be investigated.

RESULTS

In contrast with myeloablative conditioning, we observed that RIC-associated delayed-onset GVHD is characterized by low production of tumor necrosis factor-alpha, maintenance of host DC, phenotypic DC activation, increased T-regulatory cell numbers, and a delayed emergence of activated donor DC. Furthermore, changes to the peritransplant milieu in the recipient after RIC lead to the altered activation of DC and the induction of T-regulatory responses. Reduced intensity conditioning recipients suffer less early damage to GVHD target organs. However, as donor cells engraft, activated donor DC and rising levels of tumor necrosis factor-alpha are associated with a later onset of severe GVHD.

CONCLUSIONS

Delineating the mechanisms underlying delayed onset GVHD in RIC HSCT recipients is vital to improve the prediction of disease onset and allow more targeted interventions for acute GVHD.

Epigenetic inheritance of DNA methylation limits activation-induced expression of FOXP3 in conventional human CD25-CD4+ T cells

The transcription factor forkhead box P3 (FOXP3 in humans; Foxp3 in mice) controls the development and function of regulatory T cells (Treg). In mice, CD4(+)CD25(-) T cells do not express Foxp3 following TCR activation. Whether FOXP3 is a common activation-induced molecule in human T cells--hence not Treg restricted--is currently a controversial issue. As FOXP3 can significantly modulate the function of T cells, understanding the mode (and regulation) of FOXP3 expression in human T cells is vital. Here we show that in conventional CD4(+)CD25(-) T cells, the induction of FOXP3 expression following TCR activation is both restricted to a fraction of the progeny and transient. Moreover, FOXP3 expression in vivo is particularly infrequent in activated effector CD4(+) T cells that accumulate within inflamed joints. We next demonstrate that the repression of FOXP3 transcription in resting conventional human CD25(-) T cells is linked to complete methylation of an evolutionarily conserved intronic CpG island. The dense methylation pattern is furthermore inherited after activation by progeny. This intronic CpG island, on the other hand, is frequently unmethylated in CD4(+)CD25(+) T cells. Importantly, blocking maintenance DNA methylation, by pharmacological inhibition of DNA methyltransferase-1, induced significant and stable activation-dependent FOXP3 expression in cycling conventional T cells, which was further amplified by co-treatment with transforming growth factor beta. In contrast to natural Treg, such induced CD4(+)FOXP3(+) T cells could produce pro-inflammatory cytokines upon activation. These results indicate that DNA methylation normally restricts FOXP3 transcription in conventional human T cells.

TNFalpha blockade in human diseases: mechanisms and future directions

Tumor necrosis factor-alpha (TNFalpha) antagonists have shown remarkable efficacy in a variety of immune-mediated inflammatory diseases (IMIDs). Therapeutic scope and limitations of these agents are reviewed in a recently published article in the Journal. In spite of their therapeutic popularity, little is known about their modes of action in vivo and factors that limit their scope of therapeutic use. Intriguingly, while all TNFalpha antagonists including blocking antibodies and soluble receptors are effective in certain IMIDs, only anti-TNFalpha antibodies are effective in other IMIDs. Early efforts at understanding how TNFalpha antagonists act in IMIDs centered on their ability to neutralize soluble TNFalpha or to block TNF receptors from binding to their ligands. Subsequent studies suggested a role of complement-mediated lysis or antibody-dependent cell cytotoxicity in their therapeutic effects. More recent models postulate that TNFalpha blockers may act by affecting intracellular signaling, with the end result being a hastened cell cycle arrest, apoptosis, suppression of cytokine production, or improved Treg cell function. TNFalpha antagonists can also modulate the functions of myofibroblasts and osteoclasts, which might explain how TNFalpha antagonists reduce tissue damage in chronic IMIDs. Focusing on the human therapeutic experience, this analytical review will review the biology of mechanisms of action, the limiting factors contributing to disease restriction in therapeutic efficacy, and the mechanism and frequency of treatment-limiting adverse responses of TNFalpha antagonists. It is hoped that the overview will address the needs of clinicians to decide on optimal use, spur clinical innovation, and incite translational researchers to set priorities for in vivo human investigations.

Correlation of NK T-like CD3+CD56+ cells and CD4+CD25+(hi) regulatory T cells with VEGF and TNFalpha in ascites from advanced ovarian cancer: Association with platinum resistance and prognosis in patients receiving first-line, platinum-based chemotherapy

BACKGROUND

Several cytokines have been associated with immune regulation and prognosis in ovarian cancer. CD4+CD25+ Tregs and CD3+CD56+ NK-like T cells are involved in the immune response against the tumor. We have investigated the association of cytokines in the ascites from patients with ovarian cancer with these populations, the platinum resistance and the prognosis of these patients.

PATIENTS AND METHODS

Ascites from 64 patients with ovarian cancer was analysed. Forty-two patients were studied at diagnosis (FIGO stage III in 40 cases) and were treated with cytoreductive surgery and platinum-based chemotherapy. Ascites from 9 patients with cirrhosis was used as control. Vascular endothelial growth factor (VEGF), tumor necrosis factor-alpha (TNFalpha), interferon-gamma (IFNgamma), interleukin-10 (IL10) and interleukin-12 (IL12) in ascites and serum were measured by enzyme-linked immunosorbent assay (ELISA), while lymphocytic populations were studied with three-colour flow cytometry.

RESULTS

VEGF ascites levels were inversely correlated with CD3+CD56+ cells (rho=-0.316, p=0.012), while a similar correlation was observed between TNFalpha ascites levels and CD4+CD25+(hi) cells (rho=-0.332, p=0.041). Among patients receiving first-line chemotherapy, VEGF levels <1900 pg/ml and TNFalpha levels >35 pg/ml were associated with platinum sensitivity (p=0.021 and p=0.028, respectively) and improved progression-free survival (PFS) (p=0.007 and p=0.045, respectively). Low VEGF levels were also associated with improved overall survival (p=0.026).

CONCLUSION

VEGF and TNFalpha ascites levels are associated with prognosis in advanced ovarian cancer. Their prognostic significance may be due to their association with immunologically important populations, namely the NK T-like CD3+CD56+ cells and the Tregs CD4+CD25+(hi) cells.

Intercellular transfer of oncogenic H-Ras at the immunological synapse

Immune cells establish dynamic adhesive cell–cell interactions at a specific contact region, termed the immunological synapse (IS). Intriguing features of the IS are the formation of regions of plasma membrane fusion and the intercellular exchange of membrane fragments between the conjugated cells. It is not known whether upon IS formation, intact intracellular proteins can transfer from target cells to lymphocytes to allow the transmission of signals across cell boundaries. Here we show by both FACS and confocal microscopy that human lymphocytes acquire from the cells they scan the inner-membrane protein H-Ras, a G-protein vital for common lymphocyte functions and a prominent participant in human cancer. The transfer was cell contact-dependent and occurred in the context of cell-conjugate formation. Moreover, the acquisition of oncogenic H-RasG12V by natural killer (NK) and T lymphocytes had important biological functions in the adopting lymphocytes: the transferred H-RasG12V induced ERK phosphorylation, increased interferon-γ and tumor necrosis factor-α secretion, enhanced lymphocyte proliferation, and augmented NK-mediated target cell killing. Our findings reveal a novel mode of cell-to-cell communication—allowing lymphocytes to extend the confines of their own proteome—which may moreover play an important role in natural tumor immunity.

The effect of blockade of tumor necrosis factor alpha on VLA-1+ T-cells in rheumatoid arthritis patients

The alpha1beta1 integrin, very late antigen (VLA)-1, characterizes collagen adherent interferon (IFN) gamma producing memory T cells in inflamed synovium. We now report that the mean percentage of VLA-1+ T cells is significantly lower among peripheral blood mononuclear cells of rheumatoid patients responsive to antitumor necrosis factor (TNF) alpha therapy than of those with active disease not receiving therapy. Neutralization of TNFalpha during in vitro polyclonal activation of VLA-1- T cells reduced differentiation to expression of VLA-1 and inhibited secretion of IFNgamma, but did not affect integrin expression on in vivo differentiated VLA-1+ T cells. Moreover, synovial fluids of patients relapsing during and after therapy were enriched in VLA-1+ T cells and lines derived from VLA-1+ T cells in peripheral blood of treated patients retained collagen binding and secreted IFN gamma. Thus, whereas therapy decreases VLA-1+ T cells in rheumatoid arthritis patients, a subset is resistant and contributes to residual and recurring inflammation.