Human T cell development in the liver of humanized NOD/SCID/IL-2Rγ(null)(NSG) mice generated by intrahepatic injection of CD34(+) human (h) cord blood (CB) cells

In this study, we explore the possibility of human T cell development in the liver of humanized mice generated by intrahepatic injection of CD34(+) hCB cells into conditioned NOD/SCID/IL-2Rγ(null)(NSG) newborn mice. The intrahepatic injection of CD34(+) hCB cells led to effective reconstitution of human myeloid and lymphoid lineage cells. In contrast to the previously reported Rag2(-/-)γ(c)(-/-) humanized mice, interestingly, the thymus function of humanized NSG mice was markedly reduced in terms of its size and cell contents, whereas the livers of humanized NSG mice profoundly contained double-positive (DP), hCD4 and hCD8 single positive (SP), hCD34(+)hCD38(lo)hCD1a(-) (TSP), hCD34(+)hCD38(hi)hCD1a(-) (ETP), and hCD34(+)hCD38(+)hCD1a(+) (pre-T cells) cells. Furthermore, immunostaining of the liver revealed that human T cells were co-localized with hDCs. Taken together, our results demonstrate that the intrahepatic injection of hCD34(+) hCB cells can facilitate human T cell development in the livers of humanized NSG mice.     

Superior human leukocyte reconstitution and susceptibility to vaginal HIV transmission in humanized NOD-scid IL-2Rγ(-/-) (NSG) BLT mice

Humanized Bone marrow/Liver/Thymus (BLT) mice recapitulate the mucosal transmission of HIV, permitting study of early events in HIV pathogenesis and evaluation of preexposure prophylaxis methods to inhibit HIV transmission. Human hematopoiesis is reconstituted in NOD-scid mice by implantation of human fetal liver and thymus tissue to generate human T cells plus intravenous injection of autologous liver-derived CD34⁺ hematopoietic stem cells to engraft the mouse bone marrow. In side-by-side comparisons, we show that NOD-scid mice homozygous for a deletion of the IL-2Rγ-chain (NOD-scid IL-2Rγ^−/−) are far superior to NOD-scid mice in both their peripheral blood reconstitution with multiple classes of human leukocytes (e.g., a mean of 182 versus 14 CD4⁺ T cells per μl 12 weeks after CD34⁺ injection) and their susceptibility to intravaginal HIV exposure (84% versus 11% viremic mice at 4 weeks). These results should speed efforts to obtain preclinical animal efficacy data for new HIV drugs and microbicides.     

Monocytes derived from humanized neonatal NOD/SCID/IL2Rγ(null) mice are phenotypically immature and exhibit functional impairments

Trials of immune-modulating drugs in septic patients have mostly failed to demonstrate clinical efficacy. Thus, we sought to generate a surrogate model of myelomonocytic lineage differentiation that would potentially allow sepsis induction and preclinical testing of anti-inflammatory drugs. Comparing transplantation of cord blood-derived stem cells in neonatal NOD/SCID/IL2Rγ(null) (neonatal huNSG) mice with transplantation of adult peripheral mobilized stem cells into adult NSG (adult huNSG) recipients, we demonstrate that myelomonocytic lineage differentiation in neonatal huNSG mice is retarded and monocytes are phenotypically immature with respect to HLA-DR expression and the emergence of CD80(+)CD86(+) monocytes. Functionally, neonatal huNSG mice were less sensitive toward interferon-γ-induced upregulation of CD86 and exhibited a reduced T-cell stimulating capacity when compared with adult huNSG mice, whereas the phagocytic activity and the ability for cytokine secretion were mature. However, comparison of these data with data obtained from human neonates indicate that absence of the CD80(+)CD86(+) population and the reduced T-cell stimulating capacity of neonatal huNSG monocytes resemble functional immaturities observed in human neonatal monocytes. Thus, these two mouse models might well serve as 2 independent surrogate models for studying the neonatal myelomonocytic lineage differentiation or for testing the efficacy of immunomodulatory drugs on functionally mature monocytes.     

Histopathological characteristics of human non-tumor thyroid tissues in a long-term model of adenomatous goiter xenografts in the NOD/Shi-scid,IL-2Rγnull mouse

There is a growing need for modeling the human thyroid to link data obtained from animals to humans because of its sensitivity to radiation exposure and endocrine disruption chemicals. In a scid mouse model produced by transplanting human thyroid tissues, leakiness and thymic lymphoma that occurs spontaneously in the scid mouse can complicate the interpretation of experimental results. Considering that the NOD.Cg-Prkdc^scid Il2rg^tm1Sug/Jic mouse (NOD/Shi-scid, IL-2Rγ^null or NOG mouse) may be a better host because this strain has low incidence of leakiness and thymic lymphoma, we have evaluated the potential of a model that allows long-term observation of non-tumor human thyroid tissues in this mouse. We transplanted tissues of human adenomatous goiter into NOG mice and examined the tissues histopathologically. The morphology of human adenomatous goiter tissues was maintained from 24 to 44 weeks after transplantation in NOG mice with no noted differences between donor-matched tissues or the weeks after transplantation. The tissues expressed thyroglobulin protein and mRNA as well as thyroperoxidase. Endothelial cells originating from human were found in the transplanted tissues and were thought to be a characteristic of this model. The intactness of the tissues before transplantation was found to affect the rate of tissue engraftment. From the present results we have concluded that transplanted thyroid tissues in NOG mice maintain the histopathological characteristics of their origin for long terms. Therefore this model was thought feasible for toxicity evaluation.     

Generation of hematopoietic humanized mice in the newborn BALB/c-Rag2null Il2rγnull mouse model: a multivariable optimization approach

Hematopoietic humanized mice generated via transplantation of human hematopoietic stem cells (hHSCs) into immunodeficient mice are a valuable tool for studying development and function of the human immune system. This study was performed to generate a protocol that improves development and quality of humanized mice in the BALB/c-Rag2(null)Il2rγ(null) strain, testing route of injection, in vitro culture and freezing of hHSCs, types of cytokines in the culture, and co-injection of lineage-depleted CD34(-) cells. Specific hHSC culturing conditions and the addition of support cells were found to increase the frequency, and human hematopoietic chimerism, of humanized mice. The optimized protocol resulted in BALB/c-Rag2(null)Il2rγ(null) humanized mice displaying more consistent human hematopoietic and lymphoid engraftment. Thus, hematopoietic humanized mice generated on a BALB/c immunodeficient background represent a useful model to study the human immune system.     

Human B Cell Development and Antibody Production in Humanized NOD/SCID/IL-2Rγ<Superscript>null</Superscript> (NSG) Mice Conditioned by Busulfan

Background  

Busulfan treatment as a chemotherapeutic agent has been considered an alternative approach in xenograft model because it offers a simple, convenient, effective, and less toxic conditioning regimen.     

Human B-cell ontogeny in humanized NOD/SCID γc(null) mice generates a diverse yet auto/poly- and HIV-1-reactive antibody repertoire

Characterization of the human antibody (Ab) repertoire in mouse models of the human immune system is essential to establish their relevance in translational studies. Single human B cells were sorted from bone marrow and periphery of humanized NOD/SCID γc(null) (hNSG) mice at 8-10 months post engraftment with human cord blood-derived CD34(+) stem cells. Human IG variable heavy (V(H)) and kappa (V(κ)) genes were amplified, cognate V(H)-V(κ) gene-pairs assembled as single-chain variable fragment-Fc Abs (scFvFcs) and functional studies were performed. Although overall distribution of V(H) genes approximated the normal human Ab repertoire, analysis of the V(H)-third complementarity-determining regions in the mature B-cell subset demonstrated an increase in length and positive charges, suggesting autoimmune characteristics. Additionally, >70% of V(κ) sequences utilized V(κ)4-1, a germline gene associated with autoimmunity. The mature B-cell subset-derived scFvFcs displayed the highest frequency of autoreactivity and polyspecificity, suggesting defects in checkpoint control mechanisms. Furthermore, these scFvFcs demonstrated binding to recombinant HIV envelope corroborating previous observations of poly/autoreactivity in anti-HIVgp140 Abs. These data lend support to the hypothesis that anti-HIV broadly neutralizing antibodies may be derived from auto/polyspecific Abs that escaped immune elimination and that the hNSG mouse could provide a new experimental platform for studying the origin of anti-HIV-neutralizing Ab responses.     

Human T-lymphoid progenitors generated in a feeder-cell-free Delta-like-4 culture system promote T-cell reconstitution in NOD/SCID/γc(-/-) mice

Slow T-cell reconstitution is a major clinical concern after transplantation of cord blood (CB)-derived hematopoietic stem cells. Adoptive transfer of in vitro-generated T-cell progenitors has emerged as a promising strategy for promoting de novo thymopoiesis and thus accelerating T-cell reconstitution. Here, we describe the development of a new culture system based on the immobilized Notch ligand Delta-like-4 (DL-4). Culture of human CD34(+) CB cells in this new DL-4 system enabled the in vitro generation of large amounts of T-cell progenitor cells that (a) displayed the phenotypic and molecular signatures of early thymic progenitors and (b) had high T lymphopoietic potential. When transferred into NOD/SCID/γc(-/-) (NSG) mice, DL-4 primed T-cell progenitors migrated to the thymus and developed into functional, mature, polyclonal αβ T cells that subsequently left the thymus and accelerated T-cell reconstitution. T-cell reconstitution was even faster and more robust when ex vivo-manipulated and nonmanipulated CB samples were simultaneously injected into NSG mice (i.e., a situation reminiscent of the double CB transplant setting). This work provides further evidence of the ability of in vitro-generated human T-cell progenitors to accelerate T-cell reconstitution and also introduces a feeder-cell-free culture technique with the potential for rapid, safe transfer to a clinical setting.     

TNFα-dependent development of lymphoid tissue in the absence of RORγt+ lymphoid tissue inducer cells

Lymphoid tissue often forms within sites of chronic inflammation. Here we report that expression of the proinflammatory cytokine tumor necrosis factor α (TNFα) drives development of lymphoid tissue in the intestine. Formation of this ectopic lymphoid tissue was not dependent on the presence of canonical RORgt⁺ lymphoid tissue–inducer (LTi) cells, because animals expressing increased levels of TNFα but lacking RORgt⁺ LTi cells (TNF/Rorc(gt)^−/− mice) developed lymphoid tissue in inflamed areas. Unexpectedly, such animals developed several lymph nodes (LNs) that were structurally and functionally similar to those of wild-type animals. TNFα production by F4/80⁺ myeloid cells present within the anlagen was important for the activation of stromal cells during the late stages of embryogenesis and for the activation of an organogenic program that allowed the development of LNs. Our results show that lymphoid tissue organogenesis can occur in the absence of LTi cells and suggest that interactions between TNFα-expressing myeloid cells and stromal cells have an important role in secondary lymphoid organ formation.     

γ2b transgenic mice as a model for the role of immunoglobulins in B cell development

The development of B lymphocytes is tightly linked to the expression of immunoglobulins (Igs). Pro/preB cells which do not correctly rearrange heavy/light chain genes are aborted. Correctly rearranged Ig transgenes are apparently recognized by the developing B cells and can prevent the rearrangement of endogenous Ig genes. Both μ and γ2b heavy chain genes cause this feedback inhibition of heavy chain gene rearrangement. μ transgenes can in addition replace endogenous μ in its preB cell survival/maturation function. However, several different transgenic lines have shown that γ2b transgenes do not provide the nurturing functions of μ, except for one unique γ2b transgenic line, the C line. In this line mature B cells express γ2b only. Presumably, an unknown gene has been activated at the transgene integration site whose product over|comes the need for μ. The function of this gene depends of the presence of the surrogate light chain (sL), and thus must operate in combination with the preB cell receptor or in a down-stream signaling/antiapoptosis event requiring the γ2b/sL receptor. The analysis of the two types of γ2b transgenic mice shows that the signals for preB cell development are highly complex and promises to reveal new insights into the molecular and cellular mechanisms of B cell maturation.     

Nestin Delineates Pancreatic Cancer Stem Cells in Metastatic Foci of NOD/Shi-scid IL2Rγnull (NOG) Mice

Pancreatic ductal adenocarcinoma (PDAC) is associated with a high incidence of hepatic metastases, as well as occasional pulmonary metastases. To delineate the potential role of cancer stem cells (CSCs) in PDAC metastasis, human PDAC cells were injected into the spleen of mice. The characteristics and expression of markers associated with CSC and epithelial–mesenchymal transition (EMT) of metastatic cells that developed in the liver and lung were then compared with parental cells. The metastatic cells were polygonal, and larger than parental cells. Metastatic cells also exhibited decreased proliferation and increased adhesion to extracellular matrices, as well as enhanced migration and invasion in vitro and increased metastatic capacity in vivo. The CSC markers ALDH1A1, ABCG2, and nestin were expressed at high levels in metastatic cells and exhibited changes consistent with EMT (eg, decreased E-cadherin expression). Moreover, metastatic cells readily formed spheres in culture and exhibited an increased side population by flow analysis. Nestin and ABCG2 were also expressed at high levels in metastatic lesions from PDAC patients, and silencing nestin with shRNA in PDAC cells derived from lung metastases resulted in a marked decrease in the capacity of the cells to form spheres and to yield pulmonary or hepatic metastases. Thus, the metastatic potential of human PDAC cells correlates with CSCs and with EMT characteristics and is dependent on nestin expression.Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a high incidence of distant metastasis.¹ The metastatic process involves a series of complex biological processes, including migration, invasion, adhesion, and survival.² Furthermore, the extracellular matrix, interstitial cells, blood and lymph vessels, nerve fibers, and immune cells contribute to these processes. It is difficult to completely resolve the pathways that promote invasion and metastasis of PDAC cells, but elucidating the mechanisms that contribute to their enhanced metastatic efficiency is important for development of novel therapeutic approaches. Accordingly, a variety of mouse models, ranging from orthotopic models to genetically engineered mice, have been developed to study the metastatic processes that govern PDAC metastasis.Injection of human PDAC cells into the spleen of nude mice or NOD/SCID mice is a model that yields a small number of metastatic nodules in the liver.³ By contrast, in the recently developed NOD/Shi-scid IL2Rγ^null (NOG) mice (which have severe immunodeficiency, including defects in T, B, natural killer, and dendritic cell function) human pancreatic and colorectal cancer cells easily proliferate and metastasize to the liver after intrasplenic injection.⁴ It is not known, however, whether cancer stem cells (CSCs) have a role in the enhanced metastatic propensity of NOG mice. CSCs exhibit pluripotency, have the potential to self-renew, and are crucially important in cancer cell growth, invasion, metastasis, and recurrence.^5–7 CSCs preferentially spread to distant organs and contribute to the formation of lesions that phenocopy the primary tumor.⁸Given these observations, it has been suggested that targeting CSCs could provide a new therapeutic strategy in cancer.⁹ It is therefore important to examine the temporal and spatial alterations of CSCs in metastatic lesions in vivo. Furthermore, epithelial–mesenchymal transition (EMT), a fundamental mechanism controlling multiple events during metastasis,¹⁰ may generate additional CSCs endowed with a more invasive, migratory, and metastatic phenotype.¹¹ We reasoned that NOG mice would be useful for assessing the role of CSCs in the metastatic process in PDAC, because this model avoids the complexity engendered by an active immune system.In the present study, we analyzed pathological features of metastatic tumors originating from human PDAC cells. Metastatic PDAC cells exhibited lower growth rates, but higher migration and metastatic abilities. The metastatic lesions contained more CSCs than did primary tumors, and these cells exhibited a mesenchymal phenotype. Moreover, inhibition of one of the CSC markers, nestin, in metastatic PDAC cells reduced sphere formation in vitro and metastasis in vivo.     

Disturbances in the secretion of neurotransmitters in IA-2/IA-2β null mice: Changes in behavior,learning and lifespan

Islet-associated protein 2 (IA-2) and IA-2β are major autoantigens in type 1 diabetes and transmembrane proteins in dense core secretory vesicles (DCV) of neuroendocrine cells. The deletion of these genes results in a decrease in insulin secretion. The present study was initiated to test the hypothesis that this deletion not only affects the secretion of insulin, but has a more global effect on neuroendocrine secretion that leads to disturbances in behavior and learning. Measurement of neurotransmitters showed that norepinephrine, dopamine and 5-HT were significantly decreased in the brain of double knockout (DKO) mice (P<0.05 to <0.001). In tests evaluating anxiety-like behavior and conditioned-learning, the DKO mice showed a highly significant increase in anxiety-like behavior (P<0.01 to <0.001) and impairment of conditioned learning (P<0.01) as compared to WT mice. The DKO mice also displayed an increase in spontaneous and induced seizures (P<0.01) and age-related death. Contrary to the generally held view that IA-2 and IA-2β are expressed exclusively in DCV, subcellular fractionation studies revealed that IA-2β, but not IA-2, co-purifies with fractions rich in synaptic vesicles (SV), and that the secretion of dopamine, GABA and glutamate from the synaptosomes of the DKO mice was significantly decreased as was the number of SV (P<0.01). Taken together, these findings show that IA-2β is present in both DCV and SV, and that the deletion of IA-2/IA-2β has a global effect on the secretion of neurotransmitters. The impairment of secretion leads to behavioral and learning disturbances, seizures and reduced lifespan.     

The critical role of IL-12 and the IL-12Rβ2 subunit in the generation of pathogenic autoreactive Th1 cells

Experimental Allergic Encephalomyelitis (EAE) is a demyelinating disease of the central nervous system which is an animal model for the human autoimmune disease, multiple sclerosis. EAE is mediated by CD4⁺ T cells and the T cells responsible for disease induction produce Th1 cytokines. IL-12 produced by monocytes and dendritic cells is the most critical factor which influences the development and differentiation of pathogenic autoreactive Th1 cells. Here, we review our recent studies on the critical contributions of IL-12 and the IL-12Rβ2 subunit to the generation of autoreactive effector cells which mediate EAE. In addition, we discuss the potential contribution of IL-18 to the upregulation of the IL-12/IL-12Rβ2 pathway and the contribution of the suppressor cytokines, IL-4 and IL-10, in downregulating this pathway. Collectively, our studies demonstrate that the IL-12/IL-12Rβ2 pathway is a critical intermediary in the process of Th1 differentiation which can be both positively or negatively regulated. This pathway remains an attractive immunotherapeutic target for blockade of function with inhibitory reagents or downregulation by Th2 cytokines.     

Absence of IL-17A in Litomosoides sigmodontis-infected mice influences worm development and drives elevated filarial-specific IFN-γ

Parasitology Research - Lymphatic filariasis, onchocerciasis and loiasis are widespread neglected tropical diseases causing serious public health problems and impacting the socio-economic climate...     

Non-proliferating plasma cells detected in the salivary glands and bone marrow of autoimmune NOD.B10.H2b mice,a model for primary Sjögren’s syndrome

Autoantibody secreting plasma cells (PCs) are essential contributors in the development of autoimmune conditions such as primary Sjögren’s syndrome (pSS). Particularly, the long-lived PC subset residing in the bone marrow has shown to continuously produce autoantibodies, whilst remaining unaffected by immunosuppressive treatment. We have previously shown accumulation of potentially long-lived PCs in chronically inflamed salivary glands of pSS patients. In this study, we aimed to characterise the PC compartment in the salivary glands (the target organ for pSS) and bone marrow before the onset of the murine pSS like disease versus advanced diseases progression. Bromodeoxyuridine (BrdU) was incorporated to distinguish the long-lived PCs. Double immunohistochemical staining and immunofluorescence were then conducted on submandibular gland and bone marrow sections from 8- and 40-week-old mice to identify BrdU and CD138. BrdU⁺ cells were detected in the submandibular glands of 8-week-old mice, and observed within all focal infiltrates by 40 weeks of age. Most CD138⁺ PCs were however BrdU^? and located predominantly on the periphery of these infiltrates. This observation was verified through immunofluorescence. A comparable staining pattern was observed in the bone marrow of 8- and 40-week-old NOD.B10.H2b mice, where some of the CD138⁺ cells also expressed BrdU. Interestingly, megakaryocytes in the bone marrow of NOD.B10.H2b mice were detected in close proximity to CD138⁺ cells, illustrating a possible presence of PC survival niches. Our results demonstrate the presence and accumulation of potentially long-lived PCs in NOD.B10.H2b mice as the disease advances.     

Involvement of glutamate NMDA and AMPA receptors, glial cells and IL-1β in the spinal hyperalgesia evoked by the chemokine CCL2 in mice

We study here the involvement of excitatory amino acid receptors, glial cell activation and IL-1β release in the spinal hyperalgesia evoked by the chemokine CCL2 (MCP-1). Three hours after the intrathecal administration of CCL2 (1-100 ng), mice exhibit dose-dependent thermal hyperalgesia, that was inhibited by the coadministration of the antagonist of chemokine receptor type 2 (CCR2) RS504393 (0.3-3 μg). To assess the involvement of excitatory amino acid receptor sensitisation, CCL2 was coadministered with CPP (0.3-3 ng) and NBQX (25-250 ng), antagonists of NMDA and AMPA receptors, respectively. Both drugs blocked CCL2-evoked hyperalgesia, strongly suggesting that CCL2 evokes in vivo NMDA and AMPA receptor sensitisation, as previously described in electrophysiological studies. Furthermore, this rapid induction of CCL2-mediated hyperalgesia was blocked by the previous acute administration of the microglial inhibitor minocyclin (4.9 μg) or the astroglial inhibitor l-aminoadipate (1.6 μg). Since IL-1β can be released by activated glial cells we tested whether this cytokine could be underlying the spinal sensitisation induced by CCL2. The administration of the type I IL-1 receptor antagonist, IL-1ra (3-30 μg), partially prevented CCL2-evoked hyperalgesia. Finally, to elucidate if IL-1β could produce NMDA and AMPA receptor sensitisation by itself, we performed experiments in which this cytokine was i.t. administered. Thermal hyperalgesia induced by IL-1β (30 pg) was completely prevented by the coadministration of CPP (3 ng) but unaffected by NBQX (250 ng). Globally, our results suggest that spinal CCL2 induces thermal hyperalgesia by sensitising NMDA and AMPA receptors in a process that involves glial activation and IL-1β release.