T cell stimulation by dendritic cell-tumor cell hybrids is enhanced in the presence of free dendritic cells

CNPq, FAPESP (2009/54599-5 and 2012/10939-0)

Tumour cells incorporate exosomes derived from dendritic cells through a mechanism involving the tetraspanin CD9

Exosomes (Exos) are secreted nanovesicles that\ud contain membrane proteins and genetic material, which\ud can be transferred between cells and contribute to their\ud communication in the body. We show that Exos, obtained\ud from mature human dendritic cells (DCs), are incorporated\ud by tumour cells, which after Exos treatment, acquire the\ud expression of HLA‐class I, HLA‐class II, CD86, CD11c,\ud CD54 and CD18. This incorporation reaches its peak eight\ud hours after treatment, can be observed in different cell\ud tumour lines (SK‐BR‐3, U87 and K562) and could be a\ud means to transform non‐immunogenic into immunogenic\ud tumour cells. Interestingly, tetraspanins, which are\ud expressed by the tumour cells, have their surface level\ud decreased after Exo treatment. Furthermore, the intensity\ud of Exo incorporation by the different tumour cell lines was\ud proportional to their CD9 expression levels and pretreatment\ud of Exos with anti‐CD9 decreased their\ud incorporation (by SK‐BR‐3 cells). This modification of\ud tumour cells by DC‐derived Exos may allow their use in\ud new immunotherapeutic approaches to cancer.\ud Furthermore, by showing the involvement of CD9 in this\ud incorporation, we provide a possible selection criterion for\ud tumours to be addressed by this strategyFundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, #04/09956-0)Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, #07/58597-1)Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, #09/54599-5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, #303731/2007-9

Participacao do fator corda na imunopatologia da infeccao por BCG em linhagens geneticamente resistentes e susceptiveis de camundongos

BV UNIFESP: Teses e dissertaçõe

Dendritic cell-derived exosomes may be a tool for cancer immunotherapy by converting tumor cells into immunogenic targets

Dendritic cells (DCs) have been attracting attention in cancer immunotherapy because of their role in inducing and modulating effective immune responses. Besides the direct contact with other cell types and the secretion of cytokines, it is becoming clear that nanovesicles, such as exosomes (Exo), secreted by DCs also have a role in their function. Conversely, tumor-derived Exo carry antigens and have been used as a source of specific stimulus for the immune response against tumors. At the same time, several works have shown that different cells types incorporate DC-derived Exo (DC-Exo) resulting in modifications of their phenotype and function. Since DC-Exo carry many of the immune function-associated molecules of DCs, their incorporation by tumor cells could turn tumor cells into immunogenic targets. We have, therefore, treated human breast adenocarcinoma cells (SK-BR-3) with DCs-Exo and used these to stimulate previously SK-BR-3-primed CD3+ T cells. Sensitized T cells cultured with DC-Exo-treated tumor cells showed a significantly higher percentage of IFN-gamma-secreting cells (as measured by ELISPOT), when compared to the frequency of cells responding to non-DC-Exo-treated cells. These data show that the incorporation of DC-Exo by the tumor cells increased their ability to activate T cells for a possibly more effective response, thus showing that DC-Exo may become another tool in cancer immunotherap

Tolerogenic IDO+ dendritic cells are induced by PD-1-expressing mast cells

Mast cells (MC) are tissue resident cells, rich in inflammatory mediators, involved in allergic reactions, and with an increasingly recognized role in immunomodulation. Dendritic cells (DCs), on the other hand, are central to the determination of immune response patterns, being highly efficient antigen-presenting cells that respond promptly to changes in their microenvironment. Here, we show that direct cell contact between immature monocyte-derived DCs (iDCs) and MC bends DCs towards tolerance induction. DCs that had direct contact with MC (MC-iDC) decreased HLA-DR but increased PD-L1 expression and stimulated regulatory T lymphocytes, which expresses FoxP3+, secrete TGF-β and IL-10, and suppress the proliferation of mitogen-stimulated naïve T lymphocytes. Furthermore, MC-iDC expressed higher levels of indoleamine-2,3-deoxigenase (IDO), a phenomenon that was blocked by treatment of MC with anti-PD-1 or by the treatment of DCs with anti-PD-L1 or anti-PD-L2, but not by blocking of H1 and H2 histamine receptors on DCs. Contact with MC also increased phosphorylated STAT-3 levels in iDCs. When a STAT-3 inhibitor, JSI-124, was added to the DCs before contact with MC, the MC-iDC recovered their ability to induce allogeneic T cell proliferation and did not increase their IDO expression

Dendritic cells and T lymphocytes interactions in a novel 3D system

We describe the interactions between monocyte-derived DCs, in different stages of maturation, with allogeneic T lymphocytes in a 3D system. Maturation of DCs increased their interaction time with T lymphocytes from 43 to 138 minutes. The average motility of T lymphocytes interacting or not with DCs was also affected, varying from 0.21μm-0.37μm/minute to 0.36μm- 0.52μm/minute. These data indicate that this 3D BiotekTM scaffold enables interactions between lymphocytes and DCs at different stages of maturation and may be useful for the characterization of these interactions, the cellular subtypes and patterns of response induced

Altered phenotype and function of dendritic cells in individuals with chronic periodontitis

OBJECTIVE:\ud To investigate the effects of periodontal bacterial lysates on maturation and function of mature monocyte-derived dendritic cells (m-MDDCs) derived from individuals with chronic periodontitis (CP) or healthy periodontal tissue (HP).\ud \ud DESIGN:\ud m-MDDCs derived from peripheral blood monocytes, cultured for 7 days in presence of interleukin (IL)-4 and granulocyte-macrophage colony stimulating factor (GM-CSF), were stimulated with lysates of Streptococcus sanguinis, Prevotella intermedia, Porphyromonas gingivalis, or Treponema denticola on day 4, and were then phenotyped. IL-10, IL-12 and IFN-gamma concentration in the supernatant of cultures were measured.\ud \ud RESULTS:\ud Expression of HLA-DR was lower in bacterial-unstimulated mature m-MDDC from CP compared to HP (p=0.04), while expression of CD1a and CD123 were higher in CP. The expression pattern of HLA-DR, CD11c, CD123, and CD1a did not change on bacterial stimulation, regardless of the bacteria. Stimulation with P. intermedia upregulated CD80 and CD86 in CP cells (p≤0.05). Production of IL-12p70 by bacterial-unstimulated m-MDDCs was 5.8-fold greater in CP compared to HP. Bacterial stimulation further increased IL-12p70 production while decreasing IL-10. Significantly more IFN-gamma was produced in co-cultures of CP m-MDDCs than with HP m-MDDCs when cells were stimulated with P. intermedia (p=0.009).\ud \ud CONCLUSIONS:\ud Bacterial-unstimulated m-MDDC from CP exhibited a more immature phenotype but a cytokine profile biased towards proinflammatory response; this pattern was maintained/exacerbated after bacterial stimulation. P. intermedia upregulated co-stimulatory molecules and IFN-gamma expression in CP m-MDDC. These events might contribute to periodontitis pathogenesisThe State of São Paulo Research Foundation (FAPESP #04/14917-04)National Council for Scientific and Technological Development (CNPQ 304733/2006-7

Paullinia cupana Mart var. sorbilis, guaraná, reduces cell proliferation and increases apoptosis of B16/F10 melanoma lung metastases in mice

We showed that guaraná (Paullinia cupana Mart var. sorbilis) had a chemopreventive effect on mouse hepatocarcinogenesis and reduced diethylnitrosamine-induced DNA damage. In the present experiment, we evaluated the effects of guaraná in an experimental metastasis model. Cultured B16/F10 melanoma cells (5 x '10 POT. 5' cells/animal) were injected into the tail vein of mice on the 7th day of guaraná treatment (2.0 mg P. cupana/g body weight, per gavage) and the animals were treated with guaraná daily up to 14 days until euthanasia (total treatment time: 21 days). Lung sections were obtained for morphometric analysis, apoptotic bodies were counted to calculate the apoptotic index and proliferating cell nuclear antigen-positive cells were counted to determine the proliferation index. Guaraná-treated (GUA) animals presented a 68.6% reduction in tumor burden area compared to control (CO) animals which were not treated with guaraná (CO: 0.84 '+ OU -' 0.26, N = 6; GUA: 0.27 '+ OU -' 0.24, N = 6; P = 0.0043), a 57.9% reduction in tumor proliferation index (CO: 23.75 '+ OU -' 20.54, N = 6; GUA: 9.99 '+ OU -' 3.93, N = 6; P = 0.026) and a 4.85-fold increase in apoptotic index (CO: 66.95 '+ OU -' 22.95, N = 6; GUA: 324.37 '+ OU -' 266.74 'AB/mm POT. 2', N = 6; P = 0.0152). In this mouse model, guaraná treatment decreased proliferation and increased apoptosis of tumor cells, consequently reducing the tumor burden area. We are currently investigating the molecular pathways of the effects of guaraná in cultured melanoma cells, regarding principally the cell cycle inhibitors and cyclinsFAPESP 05/54195-

Dendritic cells from X-linked hyper-IgM patients present impaired responses to Candida albicans and Paracoccidioides brasiliensis

Background: Patients with X-linked hyper-IgM syndrome (X-HIGM) due to CD40 ligand (CD40L) mutations are susceptible to fungal pathogens; however, the underlying susceptibility mechanisms remain poorly understood. Objective: To determine whether monocyte-derived dendritic cells (DCs) from patients with X-HIGM exhibit normal responses to fungal pathogens. Methods: DCs from patients and controls were evaluated for the expression of costimulatory (CD80 and CD86) and MHC class II molecules and for their ability to produce IL-12 and IL-10 in response to Candida albicans and Paracoccidioides brasiliensis. We also evaluated the ability of C albicans- and P brasiliensis-pulsed mature DCs to induce autologous T-cell proliferation, generation of T helper (T-H) 17 cells, and production of IFN-gamma, TGF-beta, IL-4, IL-5, and IL-17. Results: Immature DCs from patients with X-HIGM showed reduced expression of CD80, CD86, and HLA-DR, which could be reversed by exogenous trimeric soluble CD40L. Most important, mature DCs from patients with X-HIGM differentiated by coculturing DCs with fungi secreted minimal amounts of IL-12 but substantial amounts of IL-10 compared with mature DCs from normal individuals. Coculture of mature DCs from X-HIGM patients with autologous T cells led to low IFN-g production, whereas IL-4 and IL-5 production was increased. T-cell proliferation and IL-17 secretion were normal. Finally, in vitro incubation with soluble CD40L reversed the decreased IL-12 production and the skewed T-H(2) pattern response. Conclusion: Absence of CD40L during monocyte/DC differentiation leads to functional DC abnormalities, which may contribute to the susceptibility to fungal infections in patients with X-HIGM. (J Allergy Clin Immunol 2012; 129: 778-86.)FAPESPFAPESP [2008/06635-0, 2008/55700-9, 2009/54599-5]CNPqCNPqJeffrey Modell FoundationJeffrey Modell Foundatio