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Despite recent breakthroughs of immune-checkpoint inhibitors in the management of bladder cancer (BC), only 20% of patients with non-muscle invasive BC (NMIBC) completely respond, leaving room for improvement. Due to challenges in developing a preclinical model which reflects the heterogeneity and biology of bladder tumors, patient-derived xenograft (PDX) models were created. PDX models involve implanting tumor extracted from patients into immunocompromised mice, which therefore keep the morphology and genomic fidelity of their parental patient cancers. The state of immunodeficiency, however, precludes study of immunotherapy and consequently humanized mice models engrafted with a human immune system were developed, though this led to spontaneous xenogenic graft vs host disease (GVHD). As a potential solution to GVHD in humanized mouse models, this paper describes successful creation of a double-humanized mouse (DHM) by simultaneously engrafting human immune cells and human tumors from the same donor. BC tissue was processed +/- digested into single-cell suspensions (SCS, F0 tissue) and injected orthotopically or subcutaneously into flanks of NSG™ mice. Subsequent tumor growth (PDX-F1) was measured, and PDX-F1 tumors reaching >200mm3 were processed into SCS and reimplanted subcutaneously into a new NSG™ (PDX-F2). Continuous passages (PDX-Fn) were repeated.; Extra SCS-F1 and Fn was analyzed for human epithelial cell adhesion molecule (EpCAM) expression. From an individual F1, a stable cell line (PDX257S) was cultured, and also analyzed for EpCAM expression by flow cytometry. For the DHM model, autologous γδ T-cells expanded in vitro from PDX257S donors were injected with PDX257S cells (effector: target = 2:1) into the NSG™ flanks and were observed for body condition/hematuria for 45 days. Total RNA-sequencing was performed on F0, PDX-Fn and PDX257S cell line. Tumor growth curves were analyzed with 2-way analysis of variance (ANOVA). F0 tissue was obtained from 60 patients. Tumor acceptance in orthotopic injection was not observed in the first 11 suitable tumors, and this method was ceased. Subcutaneous tumor acceptance rate improved with digestion and processing of F0 rather than processing alone (11% vs 5%). EpCAM expression was 98% vs 70% in PDX257S vs its F1 tissue, and < 30% in F1 tissue from other donors that did not yield further passages. In the DHM, while tumor growth was significantly reduced compared to control group after 45 days (mean vol 200 mm3 vs 580 mm3, p=0.02) post injection, it was not completely suppressed. RNA sequencing revealed increased expression of genes including BCL2L1, KRAS, MYC, E2F1, and E2F4 in both PDX257 subcutaneous tumor and cell line compared with donor tumor tissue, and very low/no expression of CDKN2A and FHIT genes in both PDX257 cell line and donor tumor tissue. Creation of a double-humanized mouse model is feasible, and tumor growth is not completely suppressed with the addition of autologous γδ T-cells. PDX257S tumor and cell line is associated with increased EpCAM expression and on RNA sequencing, increased expression of BCL2L1, KRAS, MYC, E2F1, and E2F4. [ABSTRACT FROM AUTHOR]

Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events (irAEs) which are more severe when ICIs are used in combination. We aimed to use a mouse model to elucidate the molecular mechanisms of immune-related hepatitis, one of the common irAEs associated with ICIs. Immune phenotyping and molecular profiling were performed on Pdcd1 -/- mice treated with anti-CTLA4 and/or the IDO1 inhibitor epacadostat or a 4-1BB agonistic antibody. ICI combination-induced hepatitis and 4-1BB agonist-mediated hepatitis share similar features yet maintain distinct immune signatures. Both were characterized by an expansion of periportal infiltrates and pan-zonal inflammation albeit with different morphologic characteristics. In both cases, infiltrates were predominantly CD4+ and CD8+ T cells with upregulated T-cell activation markers, ICOS and CD44. Depletion of CD8+ T cells abolished ICI-mediated hepatitis. Single-cell transcriptomics revealed that the hepatitis induced by combination ICIs is associated with a robust immune activation signature in all subtypes of T cells and T helper 1 skewing. Expression profiling revealed a central role for IFNγ and liver monocyte-derived macrophages in promoting a pro-inflammatory T-cell response to ICI combination and 4-1BB agonism. We developed a novel mouse model which offers significant value in yielding deeper mechanistic insight into immune-mediated liver toxicity associated with various immunotherapies. Hepatitis is one of the common immune-related adverse events in cancer patients receiving immune checkpoint inhibitor (ICI) therapy. The mechanisms of ICI-induced hepatitis are not well understood. In this paper, we identify key molecular mechanisms mediating immune intracellular crosstalk between liver T cells and macrophages in response to ICI in a mouse model. [Display omitted] • P dcd 1 -/- mouse can be utilized as a model for immune checkpoint inhibitor-mediated liver injury. • Single-cell immune transcriptional profiling revealed a landscape of molecular pathways responding to inhibition of PD1, CTLA4 and IDO1. • We identified a subset-specific T cell activation signature and common IFNγ signature. • Monocyte-derived macrophages coordinate the T cell response to immune checkpoint inhibitors. [ABSTRACT FROM AUTHOR]

CD4+CD25+Foxp3+ regulatory T (Treg) cell therapy is a promising approach for the treatment of autoimmune diseases. To be effective, Treg cells should be in an activated state in the target tissue. This can be achieved by systemic administration of Ag-specific Treg cells, which are difficult to produce in conditions that can be translated to the clinic. In this paper, we propose an alternative approach consisting of in situ injection of preactivated polyclonal Treg cells that would exert bystander suppression in the target tissue. We show that polyclonal Treg cells suppressed uveitis in mice as efficiently as Ag-specific Treg cells but only when preactivated and administered in the vitreous. Uveitis control was correlated with an increase of IL-10 and a decrease of reactive oxygen species produced by immune cell infiltrates in the eye. Thus, our results reveal a new mechanism of Treg cell-mediated suppression and a new Treg cell therapy approach. [ABSTRACT FROM AUTHOR]

Type 1 diabetes is a T cell-mediated organ-specific autoimmune disease. Antigen-specific immune intervention allows the selective targeting of autoreactive T cell, while leaving the remainder of the immune system intact. However, immune intervention for type 1 diabetes has not yielded perfect results clinically. In our paper published previously, we asked whether pancreatic duodenal home box 1 (PDX1) is a target of anti-islet autoimmunity in type 1 diabetes. In this experiment, we assessed the therapeutic effect of oral administration of PDX1 on diabetes development of 4-week-old non-obese diabetic (NOD) mice. The results indicate that PDX1 immunization is an effective intervention strategy for delaying the onset of diabetes in NOD mice in association with: 1) reduced insulitis; 2) suppression of destructive autoreactive T cells; 3) augmentation of regulatory T cells; 4) a shift in cytokine production. The present observations suggest that immunization with PDX1 modulates immune cell responses in NOD mice, raising the possibility that it is beneficial in ameliorating autoimmune destruction of beta-cells and delaying type 1 diabetes development clinically. [ABSTRACT FROM AUTHOR]

Crohn's disease and ulcerative colitis, two major forms of inflammatory bowel disease (IBD) in humans, afflicted in genetically predisposed individuals due to dysregulated immune response directed against constituents of gut flora. The defective immune responses mounted against the regulatory mechanisms amplify and maintain the IBD-induced mucosal inflammation. Therefore, restoring the balance between inflammatory and anti-inflammatory immunepathways in the gut may contribute to halting the IBD-associated tissue-damaging immune response. Phenotypic and functional characterization of various immune-suppressive T cells (regulatory T cells; Tregs) over the last decade has been used to optimize the procedures for in vitro expansion of these cells for developing therapeutic interventional strategies. In this paper, we review the mechanisms of action and functional importance of Tregs during the pathogenesis of IBD and modulating the disease induced inflammation as well as role of mouse models including humanized mice repopulated with the human immune system (HIS) to study the IBD. "Humanized" mouse models provide new tools to analyze human Treg ontogeny, immunobiology, and therapy and the role of Tregs in developing interventional strategies against IBD. Overall, humanized mouse models replicate the human conditions and prove a viable tool to study molecular functions of human Tregs to harness their therapeutic potential. [ABSTRACT FROM AUTHOR]