Divergent Effect of Cobalt and Beryllium Salts on the Fate of Peripheral Blood Monocytes and T Lymphocytes

Occupational exposure to metals such as cobalt and beryllium represents a risk factor for respiratory health and can cause immune-mediated diseases. However, the way they act may be different. We show here that the two metals have a divergent effect on peripheral T lymphocytes and monocytes: BeSO4 induces cell death in monocytes but not in T lymphocytes, which instead respond by producing Interferon gamma (IFN-γ); conversely, CoCl2 induces apoptosis in T lymphocytes but not in monocytes. Interestingly, both metals induce p53 overexpression but with a dramatic different outcome. This is because the effect of p53 in CoCl2-treated monocytes is counteracted by the antiapoptotic activity of cytoplasmic p21Cip1/WAF1, the activation of nuclear factor κB, and the inflammasome danger signaling pathway leading to the production of proinflammatory cytokines. However, CoCl2-treated monocytes do not fully differentiate into macrophage or dendritic cells, as inferred by the lack of expression of CD16 and CD83, respectively. Furthermore, the expression of HLA-class II molecules, as well as the capability of capturing and presenting the antigens, decreased with time. In conclusion, cobalt keeps monocytes in a partially activated, proinflammatory state that can contribute to some of the pathologies associated with the exposure to this meta

Divergent effect of cobalt and beryllium salts on the fate of peripheral blood monocytes and T lymphocytes.

Occupational exposure to metals such as cobalt and beryllium represents a risk factor for respiratory health and can cause immune-mediated diseases. However, the way they act may be different. We show here that the two metals have a divergent effect on peripheral T lymphocytes and monocytes: BeSO(4) induces cell death in monocytes but not in T lymphocytes, which instead respond by producing Interferon gamma (IFN-γ); conversely, CoCl(2) induces apoptosis in T lymphocytes but not in monocytes. Interestingly, both metals induce p53 overexpression but with a dramatic different outcome. This is because the effect of p53 in CoCl(2)-treated monocytes is counteracted by the antiapoptotic activity of cytoplasmic p21(Cip1/WAF1), the activation of nuclear factor κB, and the inflammasome danger signaling pathway leading to the production of proinflammatory cytokines. However, CoCl(2)-treated monocytes do not fully differentiate into macrophage or dendritic cells, as inferred by the lack of expression of CD16 and CD83, respectively. Furthermore, the expression of HLA-class II molecules, as well as the capability of capturing and presenting the antigens, decreased with time. In conclusion, cobalt keeps monocytes in a partially activated, proinflammatory state that can contribute to some of the pathologies associated with the exposure to this metal

Developing in vitro expanded CD45RA⁺ regulatory T cells as an adoptive cell therapy for Crohn's disease

BACKGROUND AND AIM: Thymus-derived regulatory T cells (T(regs)) mediate dominant peripheral tolerance and treat experimental colitis. T(regs) can be expanded from patient blood and were safely used in recent phase 1 studies in graft versus host disease and type 1 diabetes. T(reg) cell therapy is also conceptually attractive for Crohn's disease (CD). However, barriers exist to this approach. The stability of T(regs) expanded from Crohn's blood is unknown. The potential for adoptively transferred T(regs) to express interleukin-17 and exacerbate Crohn's lesions is of concern. Mucosal T cells are resistant to T(reg)-mediated suppression in active CD. The capacity for expanded T(regs) to home to gut and lymphoid tissue is unknown. METHODS: To define the optimum population for T(reg) cell therapy in CD, CD4(+)CD25(+)CD127(lo)CD45RA(+) and CD4(+)CD25(+)CD127(lo)CD45RA(−) T(reg) subsets were isolated from patients’ blood and expanded in vitro using a workflow that can be readily transferred to a good manufacturing practice background. RESULTS: T(regs) can be expanded from the blood of patients with CD to potential target dose within 22–24 days. Expanded CD45RA(+) T(regs) have an epigenetically stable FOXP3 locus and do not convert to a Th17 phenotype in vitro, in contrast to CD45RA(−) T(regs). CD45RA(+) T(regs) highly express α(4)β(7) integrin, CD62L and CC motif receptor 7 (CCR7). CD45RA(+) T(regs) also home to human small bowel in a C.B-17 severe combined immune deficiency (SCID) xenotransplant model. Importantly, in vitro expansion enhances the suppressive ability of CD45RA(+) T(regs). These cells also suppress activation of lamina propria and mesenteric lymph node lymphocytes isolated from inflamed Crohn's mucosa. CONCLUSIONS: CD4(+)CD25(+)CD127(lo)CD45RA(+) T(regs) may be the most appropriate population from which to expand T(regs) for autologous T(reg) therapy for CD, paving the way for future clinical trials

Update on Dendritic Cell-Induced Immunological and Clinical Tolerance.

Dendritic cells (DCs) as highly efficient antigen-presenting cells are at the interface of innate and adaptive immunity. As such, they are key mediators of immunity and antigen-specific immune tolerance. Due to their functional specialization, research efforts have focused on the characterization of DCs subsets involved in the initiation of immunogenic responses and in the maintenance of tissue homeostasis. Tolerogenic DCs (tolDCs)-based therapies have been designed as promising strategies to prevent and control autoimmune diseases as well as allograft rejection after solid organ transplantation (SOT). Despite successful experimental studies and ongoing phase I/II clinical trials using autologous tolDCs in patients with type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and in SOT recipients, additional basic research will be required to determine the optimal DC subset(s) and conditioning regimens for tolDCs-based treatments in vivo. In this review, we discuss the characteristics of human DCs and recent advances in their classification, as well as the role of DCs in immune regulation and their susceptibility to in vitro or in vivo manipulation for the development of tolerogenic therapies, with a focus on the potential of tolDCs for the treatment of autoimmune diseases and the prevention of allograft rejection after SOT

Trvalo udrzatelne vyuzivanie pody Vymedzenie a hodnotenie indikatorov a parametrov vyvoja pody

Available from Slovak Centre of Scientific and Technical Information, under shelf-number: A589546 / Slovenska Technicka Univerzita v BratislaveSIGLESKSlovak Republi

Impact of immunosuppressive drugs on the therapeutic efficacy of ex vivo expanded human regulatory T cells

Immunosuppressive drugs in clinical transplantation are necessary to inhibit the immune response to donor antigens. Although they are effective in controlling acute rejection, they do not prevent long-term transplant loss from chronic rejection. In addition, immunosuppressive drugs have adverse side effects, including increased rate of infections and malignancies. Adoptive cell therapy with human Tregs represents a promising strategy for the induction of transplantation tolerance. Phase I/II clinical trials in transplanted patients are already underway, involving the infusion of Tregs alongside concurrent immunosuppressive drugs. However, it remains to be determined whether the presence of immunosuppressive drugs negatively impacts Treg function and stability. We tested in vitro and in vivo the effects of tacrolimus, mycophenolate and methylprednisolone (major ISDs used in transplantation) on ex vivo expanded, rapamycin-treated human Tregs. The in vitro results showed that these drugs had no effect on phenotype, function and stability of Tregs, although tacrolimus affected the expression of chemokine receptors and IL-10 production. However, viability and proliferative capacity were reduced in a dose-dependent manner by all the three drugs. The in vivo experiments using a humanized mouse model confirmed the in vitro results. However, treatment of mice with only rapamycin maintained the viability, function and proliferative ability of adoptively transferred Tregs. Taken together, our results suggest that the key functions of ex vivo expanded Tregs are not affected by a concurrent immunosuppressive therapy. However, the choice of the drug combination and their timing and dosing should be considered as an essential component to induce and maintain tolerance by Treg

Cell therapy to promote transplantation tolerance:a winning strategy?

Organ transplantation is currently the only effective treatment for end-stage organ failure. However, success is limited by the immune response of the recipient to allogeneic tissues (recognized by the direct and indirect alloresponses) and by the morbidity and mortality associated with the immunosuppressive drugs that are used to control alloimmunity. One solution to these problems is the induction of immunological tolerance. In our laboratory, we have selected two strategies to achieve this goal. The first is to expand and/or generate Tregs directly in vivo using infusions of ‘tolerogenic’ DCs into patients; the second is to purify Tregs from the blood of patients on the waiting list for a transplant, enrich and expand these cells in vitro and then inject back in vivo after transplantation. Here, we have summarized our results both in the murine and human systems on the use of Treg-based strategies to induce tolerance to the transplanted organs. </jats:p