Cancers are immunologically heterogeneous. A range of immunotherapies target abnormal tumor immunity via different mechanisms of actions (MOAs), particularly various tumor-infiltrate leukocytes (TILs). We modeled loss of function (LOF) in four common anti-PD-1 antibody-responsive syngeneic tumors, MC38, Hepa1-6, CT-26 and EMT-6, by systematical depleting a series of TIL lineages to explore the mechanisms of tumor immunity and treatment. CD8+-T-cells, CD4+-T-cells, Treg, NK cells and macrophages were individually depleted through either direct administration of anti-marker antibodies/reagents or using DTR (diphtheria toxin receptor) knock-in mice, for some syngeneic tumors, where specific subsets were depleted following diphtheria toxin (DT) administration. These LOF experiments revealed distinctive intrinsic tumor immunity and thus different MOAs in their responses to anti-PD-1 antibody among different syngeneic tumors. Specifically, the intrinsic tumor immunity and the associated anti-PD-1 MOA were predominately driven by CD8+ cytotoxic TILs (CTL) in all syngeneic tumors, excluding Hepa1-6 where CD4+ Teff TILs played a key role. TIL-Treg also played a critical role in supporting tumor growth in all four syngeneic models as well as M2-macrophages. Pathway analysis using pharmacodynamic readouts of immuno-genomics and proteomics on MC38 and Hepa1-6 also revealed defined, but distinctive, immune pathways of activation and suppression between the two, closely associated with the efficacy and consistent with TIL-pharmacodynamic readouts. Understanding tumor immune-pathogenesis and treatment MOAs in the different syngeneic animal models, not only assists the selection of the right model for evaluating new immunotherapy of a given MOA, but also can potentially help to understand the potential disease mechanisms and strategize optimal immune-therapies in patients.
Inadequate β-cell mass is essential for the pathogenesis of type 2 diabetes (T2D). Previous report showed that an immunomodulator FTY720, a sphingosine 1-phosphate (S1P) receptor modulator, sustainably normalized hyperglycemia by stimulating β-cell in vivo regeneration in db/db mice. We further examined the effects of FTY720 on glucose homeostasis and diabetic complications in a translational nonhuman primate (NHP) model of spontaneously developed diabetes. The male diabetic cynomolgus macaques of 18-19 year old were randomly divided into Vehicle (Purified water, n = 5) and FTY720 (5 mg/kg, n = 7) groups with oral gavage once daily for 10 weeks followed by 10 weeks drug free period. Compared with the Vehicle group, FTY720 effectively lowered HbA1c, blood concentrations of fasting glucose (FBG) and insulin, hence, decreased homeostatic model assessment of insulin resistance (HOMA-IR); ameliorated glucose intolerance and restored glucose-stimulated insulin release, indicating rejuvenation of β-cell function in diabetic NHPs. Importantly, after withdrawal of FTY720, FBG, and HbA1c remained at low level in the drug free period. Echocardiography revealed that FTY720 significantly reduced proteinuria and improved cardiac left ventricular systolic function measured by increased ejection fraction and fractional shortening in the diabetic NHPs. Finally, flow cytometry analysis (FACS) detected that FTY720 significantly reduced CD4 + and CD8 + T lymphocytes as well as increased DC cells in
Graft vs. host diseases (GvHD) accounts for 15-30% of deaths following allogenic hematopoietic stem cell transplantation (allo-HSCT) for treatment of malignant diseases. Acute GvHD (aGvHD) typically involves skin, gastrointestinal and hepatic inflammation, and occurs within 100 days of transplantation; Chronic GvHD (cGvHD) involves multiple organs and occurs beyond 100 days. aGvHD is largely due to the rapid activation of donor T cells (Th1, CD8+ biased), causing tissue damage and often leading to mortality; in contrast, cGvHD is Th2 biased, typically display autoimmune-like syndrome, involving both T- and B-cell. Currently, GvHD models are mostly allo-transplantations between mice, which are criticized for poor physiological relevance. Here, we present Xenotransplantation of human donor into NSG mice, which will address some of the limitation of current models. Human peripheral blood mononuclear cells (PBMC) derived from normal donors were transplanted into NSG or NSG-like strains for modeling aGvHD. Cord blood derived HSCs (hCD34+) NSG (Jackson) were transplanted for modeling cGvHD. Hosts were monitored twice weekly, including clinical observations (e.g. animal postures, activity, fur texture, and skin integrity), body weight changes, gross pathology and histopathology upon termination, along with human-immunological phenotyping of peripheral blood, spleen, lung, liver and skin by flow cytometry, histopathology and/or immunohistochemistry. In addition, GvHD novel biomarkers Elafin, IL-18, REG3α and ST2, measured by ELISA (MBL International) at baseline and post cells engraftment. NSG mice engrafted with human PBMC, or purified T-cells, from normal donors rapidly developed typical symptoms of aGvHD, as early as 4 weeks post transplantation, including severe body loss, reduced activity, hunched posture, loss of fur, severe ruffling and overall poor grooming. Significant engraftment of human CD45+ cells were detected up to 6 weeks post-engraftment dominated with CD3+ human T-cells of single positive CD4+ or CD8+ T-cells. The corresponding kinetics of clinical symptoms in parallel with the degree of engraftment of T cells suggests xenografting were responsible for aGvHD. As for the cGvHD, NSG-mice engrafted with CD34+ cells derived from cord blood with cGvHD high- risk HLA haplotypes C*0602 and C*0401. Manifestation of cGvHD was observed 18 weeks to 39 weeks post-engraftment; symptoms were similar to aGvHD, but also include facial/full body alopecia, and scaly skin. Interestingly, in correlation of this, human engraftment of CD45+, particularly T-cells including CD4+ and their CD30+ subsets, are kinetically increased in blood and spleen with similar timeline, suggesting their roles in the observed cGvHD. The xenograft murine model using adult human PBMC and cord blood derived CD34+ HSCs could be alternative experimental systems to model human aGvHD and cGvHD for investigating disease mechanisms and evaluating treatment strategy. Citation Format: Ann E. Lin, Annie X. An, Mingfa Zang, Derron Yu, Eunmi Hwang, Israel Romero, Linda Quirino, Marybeth George, Pirouz Daftarian, Wenqing Yang, Henry Li. Experimental modeling of acute- and chronic-GvHD by xenotransplanting human donor PBMCs or cord blood CD34+ cells (HSC) into NSG mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2342.
BackgroundBispecific T cell engagers (BiTE) is a fast-growing class of immunotherapies. They are bispecific antibody that bind to T cell-surface protein (for example, CD3e) and a specific tumor associate antigen (TAA) on tumor cells, by which to redirect T cells against tumor cells in a MHC-independent manner. A successful example in the clinical is Blinatumomab, a BiTE antibody against CD3/CD19 approved in 2014 to treat acute lymphoblastic leukemia. Currently, many CD3-based BiTE are in clinical trials, including BCMAxCD3, Her2xCD3, CEAxCD3, and PSMAxCD3. To evaluate the efficacy of BiTE in vitro, human peripheral blood monocyte cells (hPBMC) are commonly being used as a source of T cells to co-culture with tumor cells. The disadvantage of using hPBMC is donor-to-donor variability and the availability of the original donor if a study needs to be repeated.MethodsTo overcome this, we proposed to replace hPBMC with T cells from human CD3e (hCD3) genetically engineered mouse models mice (GEMM) for in in vitro coculture assay. T cells were isolated from hCD3 GEMM mice using negative selection mouse T cell isolation kit. Conventional tumor cell lines or luciferase-engineered patient-derived-xenograft (PDX)-derived organoids (PDXO) expressing specific antigens are co-cultured with hCD3 T cells in 96-well plates in the presence of BiTE antibody.ResultsWe measured the killing of tumor cells using either flow cytometry or luciferase activity as readouts. To analyze tumor-reactivity of T cells to cancer cell line or organoids, IFN-gamma in the culture medium was measured and activation markers on T cells was assessed.ConclusionsOur data showed the feasibility of using humanized mice T cells as a replacement for hPBMCs to assess BiTE antibody in vitro. We are further validating the application of murine hCD3 T cells for in vivo models to test bispecific T cell engagers.
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