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Human macrophages and dendritic cells can equally present MART-1 antigen to CD8(+) T cells after phagocytosis of gamma-irradiated melanoma cells.

ABSTRACT: Dendritic cells (DC) can achieve cross-presentation of naturally-occurring tumor-associated antigens after phagocytosis and processing of dying tumor cells. They have been used in different clinical settings to vaccinate cancer patients. We have previously used gamma-irradiated MART-1 expressing melanoma cells as a source of antigens to vaccinate melanoma patients by injecting irradiated cells with BCG and GM-CSF or to load immature DC and use them as a vaccine. Other clinical trials have used IFN-gamma activated macrophage killer cells (MAK) to treat cancer patients. However, the clinical use of MAK has been based on their direct tumoricidal activity rather than on their ability to act as antigen-presenting cells to stimulate an adaptive antitumor response. Thus, in the present work, we compared the fate of MART-1 after phagocytosis of gamma-irradiated cells by clinical grade DC or MAK as well as the ability of these cells to cross present MART-1 to CD8(+) T cells. Using a high affinity antibody against MART-1, 2A9, which specifically stains melanoma tumors, melanoma cell lines and normal melanocytes, the expression level of MART-1 in melanoma cell lines could be related to their ability to stimulate IFN-gamma production by a MART-1 specific HLA-A*0201-restricted CD8(+) T cell clone. Confocal microscopy with Alexa Fluor®(647)-labelled 2A9 also showed that MART-1 could be detected in tumor cells attached and/or fused to phagocytes and even inside these cells as early as 1 h and up to 24 h or 48 h after initiation of co-cultures between gamma-irradiated melanoma cells and MAK or DC, respectively. Interestingly, MART-1 was cross-presented to MART-1 specific T cells by both MAK and DC co-cultured with melanoma gamma-irradiated cells for different time-points. Thus, naturally occurring MART-1 melanoma antigen can be taken-up from dying melanoma cells into DC or MAK and both cell types can induce specific CD8(+) T cell cross-presentation thereafter.

SUBMITTER: Barrio MM

PROVIDER: S-EPMC3388056 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Human macrophages and dendritic cells can equally present MART-1 antigen to CD8(+) T cells after phagocytosis of gamma-irradiated melanoma cells.

Barrio María Marcela MM Abes Riad R Colombo Marina M Pizzurro Gabriela G Boix Charlotte C Roberti María Paula MP Gélizé Emmanuelle E Rodriguez-Zubieta Mariana M Mordoh José J Teillaud Jean-Luc JL

PloS one 20120702 7

Dendritic cells (DC) can achieve cross-presentation of naturally-occurring tumor-associated antigens after phagocytosis and processing of dying tumor cells. They have been used in different clinical settings to vaccinate cancer patients. We have previously used gamma-irradiated MART-1 expressing melanoma cells as a source of antigens to vaccinate melanoma patients by injecting irradiated cells with BCG and GM-CSF or to load immature DC and use them as a vaccine. Other clinical trials have used I ...[more]

PMID: 22768350

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Project description:Background/aimThe uveal compartment of the eye contains extensive networks of resident macrophages and dendritic cells. These cells are now recognised to have a role in many ocular pathologies. The aim of this study was to isolate, characterise, and compare the function of ciliary body/choroid dendritic cells and macrophages from the normal eye.MethodsExplants of rat and human ciliary body/choroid were cultured in vitro for various periods of time and cells harvested either from the supernatant fluid or from enzyme digested and washed explants. The cells were then phenotyped by microscopy and flow cytometry, examined by video time lapse photomicroscopy, and analysed functionally in a series of immunoassays.ResultsTwo main types of dendritic cell were identified: large veil-like MHC class II(mid) motile but relatively non-translocatory cells and small MHC class II(hi) motile and rapidly translocating cells. Tissue macrophages mainly remained associated with the explants in culture but gradually lost their resident tissue marker (ED2) and detached from the explants as clusters of low density, large, CR3 (ED7)(+) cells, some of which underwent apoptosis. Video time lapse studies showed dendritic cells constantly interacting with large single cells and cell clusters by traversing the interstices of the cell clusters. In functional studies, freshly isolated dendritic cells were poor presenters of antigen and required activation by short term culture for acquisition of antigen presenting function. In contrast, dendritic cell depleted choroidal cell preparations containing macrophages and other cells failed to present antigen even after short term culture but augmented the antigen presenting function of dendritic cells when tested in co-culture.ConclusionAt least two types of dendritic cells are present in the normal ciliary body/choroid layer of the eye. It is likely that these cells have different functions based on their motility and potential to migrate to secondary lymphoid tissue either during normal physiological homeostatic processes or during an inflammatory response. The behaviour of resident tissue myeloid cells may decide the outcome of the organism's response to stress, foreign antigen, and ageing processes such as age related macular degeneration.

Project description:BackgroundSince numerous pathological conditions are evoked by unwanted dendritic cell (DC) activity, therapeutic agents modulating DC functions are of great medical interest. In regenerative medicine, cellular secretomes have gained increasing attention and valuable immunomodulatory properties have been attributed to the secretome of γ-irradiated peripheral blood mononuclear cells (PBMCs). Potential effects of the PBMC secretome (PBMCsec) on key DC functions have not been elucidated so far.MethodsWe used a hapten-mediated murine model of contact hypersensitivity (CH) to study the effects of PBMCsec on DCs in vivo. Effects of PBMCsec on human DCs were investigated in monocyte-derived DCs (MoDC) and ex vivo skin cultures. DCs were phenotypically characterised by transcriptomics analyses and flow cytometry. DC function was evaluated by cytokine secretion, antigen uptake, PBMC proliferation and T-cell priming.FindingsPBMCsec significantly alleviated tissue inflammation and cellular infiltration in hapten-sensitized mice. We found that PBMCsec abrogated differentiation of MoDCs, indicated by lower expression of classical DC markers CD1a, CD11c and MHC class II molecules. Furthermore, PBMCsec reduced DC maturation, antigen uptake, lipopolysaccharides-induced cytokine secretion, and DC-mediated immune cell proliferation. Moreover, MoDCs differentiated with PBMCsec displayed diminished ability to prime naïve CD4+T-cells into TH1 and TH2 cells. Furthermore, PBMCsec modulated the phenotype of DCs present in the skin in situ. Mechanistically, we identified lipids as the main biomolecule accountable for the observed immunomodulatory effects.InterpretationTogether, our data describe DC-modulatory actions of lipids secreted by stressed PBMCs and suggest PBMCsec as a therapeutic option for treatment of DC-mediated inflammatory skin conditions.FundingThis research project was supported by the Austrian Research Promotion Agency (Vienna, Austria; grant "APOSEC" 862068; 2015-2019) and the Vienna Business Agency (Vienna, Austria; grant "APOSEC to clinic" 2343727).

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Human macrophages and dendritic cells can equally present MART-1 antigen to CD8(+) T cells after phagocytosis of gamma-irradiated melanoma cells.

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Human macrophages and dendritic cells can equally present MART-1 antigen to CD8(+) T cells after phagocytosis of gamma-irradiated melanoma cells.

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