Obesity is a disease characterized by chronic low-grade systemic inflammation and has been causally linked to the development of 13 cancer types. Several studies have been undertaken to determine if tumors evolving in obese environments adapt differential interactions with immune cells and if this can be connected to disease outcome. Most of these studies have been limited to single cell lines and tumor models and analysis of limited immune cell populations. Given the multicellular complexity of the immune system and its dysregulation in obesity, we applied high-dimensional suspension mass cytometry to investigate how obesity affects tumor immunity. We used a 36-marker immune-focused mass cytometry panel to interrogate the immune landscape of orthotopic syngeneic mouse models of pancreatic and breast cancer. Unanchored batch correction was implemented to enable simultaneous analysis of tumor cohorts to uncover the immunotypes of each cancer model and reveal remarkably model-specific immune regulation. In the E0771 breast cancer model, we demonstrate an important link to obesity with an increase in two T cell suppressive cell types and a decrease in CD8 T-cells.

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Obesity is a disease characterized by chronic low-grade systemic inflammation and has been causally linked to the development of 13 cancer types. Several studies have been undertaken to determine if tumors evolving in obese environments adapt differential interactions with immune cells and if this can be connected to disease outcome. Most of these studies have been limited to single cell lines and tumor models and analysis of limited immune cell populations. Given the multicellular complexity of the immune system and its dysregulation in obesity, we applied high-dimensional suspension mass cytometry to investigate how obesity affects tumor immunity. We used a 36-marker immune-focused mass cytometry panel to interrogate the immune landscape of orthotopic syngeneic mouse models of pancreatic and breast cancer. Unanchored batch correction was implemented to enable simultaneous analysis of tumor cohorts to uncover the immunotypes of each cancer model and reveal remarkably model-specific immune regulation. In the E0771 breast cancer model, we demonstrate an important link to obesity with an increase in two T cell suppressive cell types and a decrease in CD8 T-cells.

RATIONALE: Studies show that mast cells (MCs), by releasing preformed mediators and expression of diverse molecules, can have a direct effect on the initiation of an immune response prior to IgE production. To determine the role of MCs in orchestrating an immune response, a complex tissue model was developed to mimic human physiology. In this work, the model was used to investigate the interaction between monocytes and MCs in response to an allergen in an IgE-independent manner. METHODS: MC progenitors, isolated from human peripheral blood, along with human fibroblasts were cultured in a collagen matrix and the apical surface was seeded with human endothelial cells, to mimic a layer of tissue. After MC generation, samples were activated with D. pteronyssinus extract and autologous monocytes were added to the apical endothelial layer. Samples were incubated for 3 h for monocytes to migrate across the endothelial layer and remaining cells were washed away. After 48 h, cells that reverse-transmigrated across the endothelial layer and remaining within the subendothelial layer were collected and analyzed by flow cytometry to determine the differentiation of monocytes into dendritic cells (DCs). Samples without allergen or MCs served as control groups. RESULTS: Monocytes in response to the allergen upregulated the expression of CD1c and HLA-DR, while down regulating the expression of CD14, CD64, and CD16 in comparison with controls. The differentiated cells possessed CD86, CD83, TSLPR, and marginally OX40L. CONCLUSIONS: Monocytes in response to the allergen or allergenactivated MCs within the collagen matrix differentiated to CD1c + cells, displaying phenotypic characteristics of DCs.