Expression of IL-1 Family Cytokines in Patients Before and After Cutaneous Leishmaniasis Cure

Cutaneous leishmaniasis is an infectious disease that presents an immune response marked by the activation of lymphocytes and production of cytokines, including those of the IL-1 family, which act as an important trigger for the activation of an effector immune response. Despite this, inflammation exacerbation is sometimes also attributed to IL-1 cytokines, although some others down-regulate inflammation or produce Th2 responses, which need to be further clarified in the CL. Assessing the gene and protein expression of IL-1 cytokines associated with different immune response profiles in PBMCs from patients with active and healed lesions, this study demonstrated that stimulation by L. braziliensis positively regulates inflammatory and anti-inflammatory IL-1 cytokines, as IL-1α/β and IL-37, while there was a marked inhibition of IL-1Ra and IL-18 genes in patients treated with antimony, which perhaps contributes to the mechanisms of resistance that control Leishmania infection.

Increased Tc17 cell levels and imbalance of naïve/effector immune response in Parkinson’s disease patients in a two-year follow-up: a case control study

Background Neuroinflammation has been proved to play a role in dopaminergic neuronal death in Parkinson’s disease (PD). This link highlights the relevance of the immune response in the progression of the disease. However, little is known about the impact of peripheral immune response on the disease. This study is aimed to evaluate how immune cell populations change in untreated PD patients followed-up for 2 years. Methods Thirty-two patients with no previous treatment (PD-0 yr) and twenty-two healthy subjects (controls) were included in the study. PD patients were sampled 1 and 2 years after the start of the treatment. CD4 T cells (naïve/central memory, effector, and activated), CD8 T cells (activated, central memory, effector memory, NKT, Tc1, Tc2, and Tc17), and B cells (activated, plasma, and Lip-AP) were characterized by flow cytometry. Results We observed decreased levels of naïve/central memory CD4 and CD8 T cells, Tc1, Tc2, NKT, and plasma cells, and increased levels of effector T cells, activated T cells, and Tc17. Conclusions PD patients treated for 2 years showed an imbalance in the naive/effector immune response. Naïve and effector cell levels were associated with clinical deterioration. These populations are also correlated to aging. On the other hand, higher Tc17 levels suggest an increased inflammatory response, which may impact the progression of the disease. Our results highlight the relevant effect of treatment on the immune response, which could improve our management of the disease.

Regulatory T Cells: Barriers of Immune Infiltration Into the Tumor Microenvironment

Regulatory T cells (Tregs) are key immunosuppressive cells that promote tumor growth by hindering the effector immune response. Tregs utilize multiple suppressive mechanisms to inhibit pro-inflammatory responses within the tumor microenvironment (TME) by inhibition of effector function and immune cell migration, secretion of inhibitory cytokines, metabolic disruption and promotion of metastasis. In turn, Tregs are being targeted in the clinic either alone or in combination with other immunotherapies, in efforts to overcome the immunosuppressive TME and increase anti-tumor effects. However, it is now appreciated that Tregs not only suppress cells intratumorally via direct engagement, but also serve as key interactors in the peritumor, stroma, vasculature and lymphatics to limit anti-tumor immune responses prior to tumor infiltration. We will review the suppressive mechanisms that Tregs utilize to alter immune and non-immune cells outside and within the TME and discuss how these mechanisms collectively allow Tregs to create and promote a physical and biological barrier, resulting in an immune-excluded or limited tumor microenvironment.

Relevance of Regulatory T Cells during Colorectal Cancer Development

In recent years, there has been a significant increase in the study of own and foreign human factors favoring the development of different types of cancer, including genetic and environmental ones. However, the fact that the immune response plays a fundamental role in the development of immunity and susceptibility to colorectal cancer (CRC) is much stronger. Among the many cell populations of the immune system that participate in restricting or favoring CRC development, regulatory T cells (Treg) play a major role in orchestrating immunomodulation during CRC. In this review, we established concrete evidence supporting the fact that Treg cells have an important role in the promotion of tumor development during CRC, mediating an increasing suppressive capacity which controls the effector immune response, and generating protection for tumors. Furthermore, Treg cells go through a process called “phenotypic plasticity”, where they co-express transcription factors that promote an inflammatory profile. We reunited evidence that describes the interaction between the different effector populations of the immune response and its modulation by Treg cells adapted to the tumor microenvironment, including the mechanisms used by Treg cells to suppress the protective immune response, as well as the different subpopulations of Treg cells participating in tumor progression, generating susceptibility during CRC development. Finally, we discussed whether Treg cells might or might not be a therapeutic target for an effective reduction in the morbidity and mortality caused by CRC.

ERM Proteins at the Crossroad of Leukocyte Polarization, Migration and Intercellular Adhesion

Ezrin, radixin and moesin proteins (ERMs) are plasma membrane (PM) organizers that link the actin cytoskeleton to the cytoplasmic tail of transmembrane proteins, many of which are adhesion receptors, in order to regulate the formation of F-actin-based structures (e.g., microspikes and microvilli). ERMs also effect transmission of signals from the PM into the cell, an action mainly exerted through the compartmentalized activation of the small Rho GTPases Rho, Rac and Cdc42. Ezrin and moesin are the ERMs more highly expressed in leukocytes, and although they do not always share functions, both are mainly regulated through phosphatidylinositol 4,5-bisphosphate (PIP2) binding to the N-terminal band 4.1 protein-ERM (FERM) domain and phosphorylation of a conserved Thr in the C-terminal ERM association domain (C-ERMAD), exerting their functions through a wide assortment of mechanisms. In this review we will discuss some of these mechanisms, focusing on how they regulate polarization and migration in leukocytes, and formation of actin-based cellular structures like the phagocytic cup-endosome and the immune synapse in macrophages/neutrophils and lymphocytes, respectively, which represent essential aspects of the effector immune response.

Immunomodulatory Effects of Histone Deacetylase 6 Inhibition in Suppressor Immune Cells in Multiple Myeloma

Abstract 128 The interaction of myeloma (MM) cells with bone marrow accessory cells and/or the extracellular matrix induces genomic, epigenomic and functional changes which promote tumor development, progression, cell adhesion mediated-drug resistance (CAM-DR), and immune suppression. To develop the most efficient anti-MM treatment strategy and prevent tumor escape from immune recognition, both enhancing anti-MM effector immune response and overcoming MM-induced immune suppression is essential. Suppressive immune cells including myeloid derived suppressor cells (MDSC), regulatory T cells (Treg) and IL-17 secreting Th (Th17) cells act as tumor promoters and suppressors of effector immune response, and therefore represent a significant barrier to current anti-tumor therapeutic strategies. Since, we and others have reported increased numbers of Treg and Th17 cells in MM, we here assessed MDSCs in both peripheral blood (PBMC) and bone marrow (BMMC) of patients with MM compared to healthy donors. Phenotypic analysis by flow cytometry showed a significant increase in CD14−CD11b+HLA-DRlowCD15+ MDSCs in both PBMC and BMMC from MM patients compared to healthy donors (p<0.01). Furthermore, coculture of MM cell lines with healthy PBMCs for 6 days demonstrated that MM cells significantly induce MDSC differentiation in healthy PBMCs (p<0.03). Recent studies have demonstrated that histone deacytlase 6 (HDAC6) is an important regulator of monocyte/macrophage-mediated immune response. We therefore next analysed the immunomodulatory effects of WT-161, a novel small molecule inhibitor of HDAC6, alone or in combination with lenalidomide (len) and bortezomib (bort), on suppressive immune cells in the MMBM microenvironment. To keep cell-cell interaction intact reflective of the MMBM microenvironment, PBMCs or BMMCs from MM patients were cultured in the absence or presence of WT-161 (0.5–5uM), len (1–10uM), and/or bort (2–5nM), and individual cell populations were analysed by flow cytometry. Phenotypic characterization of suppressive immune cells showed a significant decrease in both CD4+CD25+Foxp3+ Treg cells and MDSCs in MM-PBMCs and MM-BMMCs cultured with WT-161, alone or in combination with len or bort (p<0.01); however, there was no change in the expression of Th17 cells. To determine the functional mechanism of immune suppression, MDSC and Treg cells were isolated by magnetic-Ab sorting and cultured for 6 days with autologous T cells (TCR/IL-2 stimulated), with or without WT-161, len and bort, alone or in combination. T cell proliferation (by 3H-thymidine assay) was significantly inhibited in the presence of MDSCs, whereas WT-161 notably reversed MDSC-mediated T cell suppression. In contrast, len and bort did not show any significant effect. Intracellular reactive oxygen species (ROS, an MDSC-derived metabolic immune inhibitory molecule) expression was significantly decreased in MDSCs from MM cultured with WT-161, alone or together with len and bort (p<0.05). Additionally, WT-161 also reversed Treg-mediated T cell suppression as well as len. Cytokine profiling by intracellular flow cytometric analysis demonstrated that WT-161 significantly decreased IL-6 and GM-CSFR expression in MDSCs, whereas it induced IFNγ and IL-12 production in effector CD4T, CD8T and NKT cells. Finally, unstimulated or IL-2 prestimulated (36h) PBMCs or NK cells were cultured with MM cell lines (MM1.S, RPMI8226), in the absence or presence of WT-161 alone or with len and bort (4h), and anti-MM cytotoxic activity was determined by Cr51-release cytotoxicity assay. While len (48% killing) and WT-161 (39% killing) induced CTL-mediated cytotoxicity, WT-161 (53% killing) and len (56% killing) induced more potent NK cell-mediated anti-MM cytotoxicity. These data suggest that HDAC6 may have an immune regulatory function, and that inhibition of HDAC6 induces changes in suppressor immune cells leading to enhanced anti-MM immune response in MM microenvironment. Ongoing analysis of the effects of HDAC6 inhibition on immune cells in the tumor microenvironment will further define the role of HDAC6 in disease pathogenesis and suggest novel immune-based epigenetic-targeted therapies. Disclosures: Hideshima: Acetylon: Consultancy. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Acetylon: Research Funding. Bradner:Acetylon: Scientific Founder. Richardson:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees. Munshi:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Membership on an entity's Board of Directors or advisory committees. Anderson:Novartis: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acetylon: Membership on an entity's Board of Directors or advisory committees.