This research is part of an effort to develop non-mammalian surrogate immunoessays with the earth worm Lumbricus terrestris to assess immunotoxic potential of xenobiotics to mammals. The objective was to determine if earthworm immunoessays, namely E- and S- rosette formation and phagocytosis, are sensitive to a known mammalian immunotoxin, the PCB Arclor 1254. Results are presented in terms of PCB exposure and tissue concentrations during uptake/depuration.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

No description available.

<p>The pathogenesis of Alzheimer’s disease (AD) is a critical unsolved question, and while recent studies have demonstrated a strong association between altered brain immune responses and disease progression, the mechanistic cause of neuronal dysfunction and death is unknown. We have previously described the unique CVN-AD mouse model of AD, in which immune-mediated nitric oxide is lowered to mimic human levels, resulting in a mouse model that demonstrates the cardinal features of AD, including amyloid deposition, hyperphosphorylated and aggregated tau, behavioral changes and age-dependent hippocampal neuronal loss. Using this mouse model, we studied longitudinal changes in brain immunity in relation to neuronal loss and, contrary to the predominant view that AD pathology is driven by pro-inflammatory factors, we find that the pathology in CVN-AD mice is driven by local immune suppression. Areas of hippocampal neuronal death are associated with the presence of immunosuppressive CD11c+ microglia and extracellular arginase, resulting in arginine catabolism and reduced levels of total brain arginine. Pharmacologic disruption of the arginine utilization pathway by an inhibitor of arginase and ornithine decarboxylase protected the mice from AD-like pathology and significantly decreased CD11c expression. Our findings strongly implicate local immune-mediated amino acid catabolism as a novel and potentially critical mechanism mediating the age-dependent and regional loss of neurons in humans with AD.</p><p>There is a large interest in identifying, lineage tracing, and determining the physiologic roles of monophagocytes in Alzheimer’s disease. While Cx3cr1 knock-in fluorescent reporting and Cre expressing mice have been critical for studying neuroimmunology, mice that are homozygous null or hemizygous for CX3CR1 have perturbed neural development and immune responses. There is, therefore, a need for similar tools in which mice are CX3CR1+/+. Here, we describe a mouse where Cre is driven by the Cx3cr1 promoter on a bacterial artificial chromosome (BAC) transgene (Cx3cr1-CreBT) and the Cx3cr1 locus is unperturbed. Similarly to Cx3cr1-Cre knock-in mice, these mice express Cre in Ly6C-, but not Ly6C+, monocytes and tissue macrophages, including microglia. These mice represent a novel tool that maintains the Cx3cr1 locus while allowing for selective gene targeting in monocytes and tissue macrophages.</p><p>The study of immunity in Alzheimer’s requires the ability to identify and quantify specific immune cell subsets by flow cytometry. While it is possible to identify lymphocyte subsets based on cell lineage-specific markers, the lack of such markers in brain myeloid cell subsets has prevented the study of monocytes, macrophages and dendritic cells. By improving on tissue homogenization, we present a comprehensive protocol for flow cytometric analysis, that allows for the identification of several cell types that have not been previously identified by flow cytometry. These cell types include F4/80hi macrophages, which may be meningeal macrophages, IA/IE+ macrophages, which may represent perivascular macrophages, and dendritic cells. The identification of these cell types now allows for their study by flow cytometry in homeostasis and disease.</p> / Dissertation

Call number: LD2668 .T4 1986 J46 / Master of Science / Animal Science and Industry

Overexposure to UV (ultraviolet) radiation has been linked to a number of deleterious effects on human health, particularly epidermal malignancies, which consist of both melanoma and non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma. In the 1950’s, an epidermal compound known as Urocanic Acid (UCA) was discovered whose trans isoform was shown to display photoprotective effects against UV radiation. Not long after, the cis-UCA isomer was found to act as a mediator of immune suppression, causing UCA to be removed from all cosmetic products on the commercial market, most notably sunscreen. Numerous studies conducted after this finding further corroborated cis-UCA’s immunosuppressive properties, showing evidence for the ability of cis-UCA to inhibit contact hypersensitivity responses, delayed-type hypersensitivity responses, and allograft rejection. Early evidence for a mechanism of action behind cis-UCA’s immunosuppressive properties were widespread, including modulation of antigen-presenting cells, interaction with histamine receptors, and regulation of cytokine expression. The immunosuppressive nature of cis-UCA quickly became associated with an ability to facilitate cancerous progression, particularly regarding epidermal malignancies. Interesting theories were raised about the evolutionary basis for cis-UCA’s immunosuppressive nature, including speculation that cis-UCA was meant to induce immunosuppression following ultraviolet exposure in order to prevent autoimmune responses against sunburned epidermal cells. After the turn of the 20th century, new research continued to facilitate modern day understanding of the role of UCA. Evidence showed that UCA was ultimately derived from filaggrin within the stratum corneum, interacted with key immune effectors including T-lymphocytes and Langerhans cells, and potentially contributed to acidification of the stratum corneum. Despite the negative reputation cis-UCA has received in regards to facilitating skin cancer evasion of the immune system, research has shown that its immunosuppressive effects may allow it to serve as potent anti-inflammatory therapeutic. In regards to skin cancer, targeting of UCA as a therapeutic varies widely. Some have suggested using UCA as a measure of sunscreen efficacy, as an indirect target that when inhibited can reduce tumor growth, and as a biomarker for skin cancer risk. Others have begun developing UCA-based mimics that retain the benefits of UCA, while avoiding any deleterious effects. The role of UCA in non-melanoma and melanoma malignancies is not well understood, making targeting of UCA as a therapeutic challenging. The aim of this paper is to comprehensively review the scientific literature regarding the pre-21st century history of UCA, followed by an in-depth analysis of post-21st century research. The objective is to determine the overall potential of UCA to serve as a therapeutic target for UV-associated health conditions, most notably dermatologic malignancies.

A sepse é uma síndrome de resposta inflamatória sistêmica decorrente de um processo infeccioso, a qual acarreta alta taxa de mortalidade. Relatos da literatura tem demonstrado que pacientes e animais de experimentação que sobrevivem à sepse desenvolvem quadro de imunossupressão tardia, o qual contribui com a maior sucetibilidade destes a infecções secundárias. Nosso grupo demonstrou que as células T reguladoras (Tregs) participam ativamente do desenvolvimento desta imunossupressão. O Fator de Necrose Tumoral (TNF) é uma citocina pleotrópica responsável por diversas funções durante a resposta inflamatória, apresentando dois receptores responsáveis pelas suas atividades: o TNFR1 e o TNFR2. Foi demonstrando que o TNF exerce um importante papel na atividade de Tregs, induzindo a proliferação, estabilização do fenótipo e aumentando sua atividade imunossupressora, sugerindo que tais atividades sejam atribuidas ao TNFR2. Desta forma, nosso objetivo foi avaliar a participação dos receptores de TNF no desenvolvimento da imunossupressão pós-sepse. Para isso animais WT, TNFR1-/- e TNFR1/2 -/- foram submetidos à sepse grave, induzida por CLP e tratados com um suporte básico (reposição hidríca e antibioticoterapia). Inicialmente avaliamos a participação dos receptores de TNF na fase aguda da sepse. Demonstramos que nesta fase os receptores de TNF, principalmente TNFR1, apresentam um papel prejudicial na migração de neutrófilos, no controle do processo infeccioso e nas lesões de orgãos decorrentes da sepse. Posteriormente, os animais sobreviventes foram infectados com um dose subletal de L. pneumophila i.n 15 dias após a CLP. Avaliamos a participação dos receptores TNF na sucetibilidade à infecção secundária induzida por L. pneumophila em animais sobreviventes à sepse. Observamos que animais TNFR1-/- sobreviventes à sepse são mais suscetíveis, ao passo que animais TNFR1/2-/- sobreviventes à sepse são resitentes à infecção secundária em relação aos animais WT sobreviventes à sepse. Avaliamos então, a expansão de Tregs no baço destes animais sobreviventes à sepse e, observamos que animais TNFR1-/- apresentam aumento da expansão de Tregs, ao passo que os animais TNFR1/2-/- não apresentaram expansão de Tregs comparados ao WT. Observamos também que as Tregs apresentam maior densidade de receptores de TNF do que as células T convencionais e, que durante a sepse ocorre aumento da densidade destes receptores nas Tregs. Sugerimos então que possivelmente o TNFR1 seja um regulador negativo, enquanto o TNFR2 possa assumir um papel na regulação positiva na expansão de Tregs após a sepse, durante o desenvolvimento da imunossupressão. / Sepsis is a systemic inflammatory response syndrome resulting from infectious process, resulting in high mortality rate. It has been shown that septic mice and patients that survived from sepsis develop a late immunosuppression, which contributes to greater susceptibility to these secondary infections. Our group has shown that regulatory T cells (Tregs) actively participate in the development of this immunosuppression. The Tumor Necrosis Factor (TNF) is pleiotropic cytokine responsible for several processes in the inflammatory response. Two receptors are responsible for the various activities of TNF: TNFR1 and TNFR2. It have shown that TNF plays an important role in the activity of Tregs, inducing proliferation, stabilization of phenotype and increasing their immunosuppressive activity. The authors also suggested that these activities are TNFR2-mediated. Thus, our objective was to evaluate the role of TNF receptors in the acute phase of sepsis and also in the development of immunosuppression post-sepsis. For that, TNFR1-/ -, TNFR1/2 -/ - and WT mice were underwent to severe sepsis induced by CLP and treatment with basic support (hydration and antibiotics). Initially we evaluated the participation of TNF receptors in the acute phase of sepsis. We suggest that at this stage the TNF receptor, TNFR1 mainly exert a deleterious role in the migration of neutrophils in control of the infectious process and the tissue damage resulting from sepsis. In addition, the survivors from the septic event were intranasaly infected with L. pneumophila in the 15th day after sepsis induction. We evaluated the participation of these receptors in susceptibility to secondary infection induced by L. pneumophila in survivors from sepsis. Comparing the animals that survived from sepsis, we observed that TNFR1/2-/- , like WT mice, are not susceptible to the secondary infection, while TNFR1-/- survivors are more susceptible to it. We also observed that TNFR1-/ - animals show increased expansion of Tregs in the spleen, different of TNFR1/2-/- mice, that did not show expansion of Tregs compared to WT. We also observed Tregs have a higher density of receptors for TNF than conventional T cells, whereas during sepsis occurs increased expression of this receptor in Tregs. Altogether, the results suggest that TNFR1 is a negative regulator, whereas TNFR2 may play a role in the upregulation during expansion of Tregs, in development of sepsis-induced imunossupression.

Hamsteres infectados com Leishmania (L.) chagasi são considerados um dos melhores modelos para estudo de fatores relacionados à imunossupressão que ocorre durante a leishmaniose visceral ativa, pois apresenta manifestações clínicas similares ao que ocorre no homem e não conseguem controlar a infecção. Neste estudo, hamsteres infectados intraperitonealmente com 2x107 parasitos foram utilizados para avaliação de possíveis fatores envolvidos na dinâmica da imunossupressão. Os parâmetros avaliados foram a produção de citocinas de padrão Th1 e Th2, produção de óxido nítrico por células esplênicas e detecção de apoptose em linfócitos esplênicos em tempos precoces (6, 20, 48 e 72 horas), intermediários (7 e 15 dias) e tardios (30 e 60 dias) de infecção. Inicialmente avaliamos a carga parasitária no baço e observamos aumento progressivo dependente do tempo de infecção, ratificando que hamster infectado é um bom modelo para desenvolvimento de doença. A resposta celular frente a mitógeno e antígeno de Leishmania foi o parâmetro utilizado para avaliação de imunossupressão. Observamos resposta preservada à concanavalina A em todos os tempos de infecção e resposta preservada ao antígeno de Leishmania nos tempos precoces, porém com ausência de resposta antígeno específica a partir do tempo de 7 dias de infecção. A quantificação de óxido nítrico foi determinada em sobrenadante de células esplênicas de cultura estimuladas com concanavalina A e antígeno de Leishmania, pelo método de Griess. Observamos inicialmente baixo nível de produção de óxido nítrico em todos os tempos de infecção, no entanto quando as células foram estimuladas com antígeno de Leishmania observamos níveis ainda menores nos tempos de 48 e 72 horas de infecção. O perfil de citocinas produzido foi determinado pela reação em cadeia da polimerase por transcrição reversa, sendo detectado RNA mensageiro tanto de citocinas Th1, quanto Th2 em todos os tempos de infecção (precoce, intermediária e tardia), em células ex-vivo e estimuladas; e também em animais controles não infectados; não havendo um padrão de dicotomização de produção de citocinas neste modelo experimental. Detecção de apoptose em células esplênicas não aderentes (prováveis linfócitos T) ex-vivo e em cultura estimuladas com concanavalina A e antígeno de Leishmania foi avaliada pelos seguintes métodos: Anexina V, caspase 3 clivada e TUNEL por citometria de fluxo. Houve marcação da exposição de fosfatidil serina pelo método da anexina V, nos tempos de 6 horas de infecção, quando as células foram estimuladas com mitogeno ou antígeno de Leishmania; e com 48 horas e 60 dias de infecção somente quando estimuladas com antígeno de Leishmania. Em células esplênicas em cultura estimuladas com concanavalina não houve marcação de caspase 3 clivada, porém em células esplênicas ex-vivo nos tempos 20, 48 e 72 horas de infecção houve detecção de apoptose, definida por marcação de caspase 3 clivada. A marcação de células esplênicas não aderentes para quebra de DNA foi baixa em todos os tempos analisados, porém observamos aumento de marcação em células esplênicas não aderentes, estimuladas com antígeno nos tempos de 20 horas e posteriormente de 7 dias até 60 dias de infecção. Nossos resultados sugerem que a imunossupressão na leishmaniose visceral no modelo de hamsteres infectados com Leishmania (L.) chagasi é antígeno dependente e instala-se nos tempos intermediários de infecção, a partir de 7 dias. Esta imunossupressão parece estar relacionada com aumento de apoptose em linfócitos já nos tempos precoces de infecção, que pode favorecer a progressão da infecção, por ocorrer principalmente em células esplênicas antígenos reativas. Nossos dados sugerem ainda, que a imunossupressão não é decorrente da dicotomização da produção de citocinas Th1 e Th2 / Hamsters infected by Leishmania (L.) chagasi are considered one of the most remarkable models to study several characteristics related to immunosuppression, raised during active visceral leishmaniasis especially because hamsters show similar clinical manifestations as it is found in humans without surmounting the infection. In this study, hamsters infected intraperitoneally with 2x107 parasites were used to evaluate the possible factors involved in the dynamic of immunosuppression that occurs during the disease development. The evaluated parameters were the production of Th1 and Th2 cytokines profile, nitric oxide production of splenic cells and detection of apoptosis in splenic lymphocytes at early (6,20, 48 e 72 hours), intermediate (7 e 15 days) and late times (30 e 60 days) of infection. Initially, we evaluate the parasite load in the spleen and observed a progressive increase dependent on the time of infection, ratifying that infected hamsters are good models to set up the disease development. Cellular response upon mitogen or Leishmania antigen was the parameter used to evaluate the immunosuppression showing a preserved response to concanavalin A at all period of infection and a preserved response to the Leishmania antigen at all early phases however with no specific antigen response from 7 day of infection until the late phase of infection. Nitric oxide quantification was determined in the splenic cells supernatant in culture stimulated upon concanavalin A and Leishmania antigen and we observed initially low level of nitric oxide production, measured by the Griess method. Nonetheless, when the cells were stimulated upon Leishmania antigen we observed a lower level nitric oxide production at 48 and 72 hours of infection. mRNA of Th1 e Th2 cytokines profile was determined by RT-PCR at all period of infection studied in infected or non infected hamsters showing no difference at the cytokine profile in this experimental model. Detection of apoptosis in the non adherent splenic cells (probably T lymphocytes) ex-vivo and in the stimulated culture with concanavalin A and Leishmania antigen was evaluated by the following methods: annexin V-FITC, cleaved caspase 3 and TUNEL by flow cytometry analysis. There was phosphatidilserine staining by annexin method, at 6 hour of infection when cells were stimulated by mitogen or Leishmania antigen at 48 hours and 60 days of infection only when stimulated by Leishmania antigen. Splenic cells in culture stimulated by concanavalin A showed no cleaved caspase 3 staining in all period of infection studied. Otherwise, apoptosis was detected in the ex-vivo splenic cells at 20, 48 and 72 hours of infection by cleaved caspase 3 staining. We observed a low DNA break staining of non adherent splenic cells in all period analyzed, although this staining was increased in non adherent cells stimulated upon Leishmania antigen at 20 hours from 7 day of infection until 60 day of infection. Our results suggest that a visceral leishmaniasis immunosuppression in the hamsters model infected by Leishmania (L.) chagasi is antigen dependent and sets up in the intermediate phases of infection from 7 days on. This immunosuppression seems to be related to the apoptosis increase in lymphocytes already in the early period of infection probably favoring its progression especially because of its occurrence in reactive splenic antigen. Our data also suggest that the immunosuppression is not provided by dichotomization in the Th1 and Th2 cytokines profile

Introduction: NKT cells are categorised as borderline between NK and T cells, sharing phenotypic and functional characteristics of both cells, demonstrating their capacity to contritube to both pro- or anti-inflammatory processes. However, the role of these cells among lung transplant recipients remains largely unknown. The aim of this study was to determine the role of NKT cells following lung transplantation. Methods: NKT cells were quantified and characterised according to markers of: activation (CD107a, CD161, NKG2D) and immunomodulation (CD200 and CD200R) in peripheral blood and BALs. NKT cell numbers and phenotypes were correlated to clinical variables: immunosuppression, acute rejection, acute infections (viral, bacterial and fungal), bronchiolitis obliterans syndrome (BOS grade), lung function, and demographic variables. Interactions between NKT cells and the transplanted lung were linked by determining the relative expression of immunomodulatory ligand CD200 in lung biopsies. In vitro models were employed to determine the role of NKT cells to acute lung injury, either alone or in combination with cells of the mononuclear phagocyte system (MPS). Results: Higher numbers of immunomodulatory NKT cells (CD200+ and CD200R+) were found as lung function decreased. Data from peripheral blood indicates that recipients whose donors or themselves had been exposed to CMV infection demonstrated increased numbers of NKT cells. Patients with active EBV infections demonstrated higher NKT cell numbers expressing CD200 and CD200R. Data from BALs, indicates that patients with active fungal infections present higher immunomodulatory (CD200R) NKT cells and lower cytotoxicity marker (CD107a). In peripheral blood, lung recipients demonstrated higher NKT cell numbers compared to healthy volunteers. However, the lower relative mean expression of functional markers in the lung transplant group suggests that cells are less active. In vitro cultures with immunosuppressants demonstrated that cell cycle inhibitors (MMF and AZA) and corticosteroids (Prednisolone) are likely to inhibit NKT cell proliferation, while calcineurin inhibitors (Cyclosporine A and Tacrolimus) decrease the relative mean expression of activation markers. Clinical observations indicate that higher doses of Azathioprine may correlate with increased NKT cell numbers and the relative expression of CD200 and CD200R. However, under these conditions the relative expression of activation marker NKG2D decreases. In vitro data from the acute injury model indicates that NKT cells are capable to migrate into the injured lung and become activated following transmigration which is facilitated by the presence of monocytes. We also observed the interaction of NKT cells with endothelial cells, monocytes and macrophages. Also, the relative mean expression of CD200 and CD200R increased at the capillary layer, regardless of injury while upregulation of activation markers (CD107a, CD161 and NKG2D) was found at the capillary layer, following injury. In contrast, the alveolar layer demonstrated a decrease in both activation and immunomodulatory markers, following acute injury. Conclusions: Despite immunosuppression, NKT cells remain present in peripheral blood and BAL following lung transplantation. NKT cell proliferation is likely to be reduced by effect of cell cycle inhibitors, while calcineurin inhibitors exert an immunomodulatory effect. Our data indicates that NKT cells can participate in inflammatory and immunomodulatory events at the alveolar bilayer. Their capacity to infiltrate the lungs was assisted by cells of the mononuclear phagocyte system (MPS), which play an important role in antigen presentation and modulation of acute injury. Further research is needed to elucidate the signals and mechanisms occurring between NKT and MPS interactions and the outcomes these populations drive in acute lung injury.

It is well recognized that regulatory T cells (Tregs) are immunosuppressive, by which they prevent systemic autoimmunity throughout life. Beyond this stereotypical function, however, a growing body of evidence demonstrates that Tregs in distinct tissues, including the visceral adipose tissue, dystrophic muscle, the flu-infected lung, and wounded skin can acquire unique functions directed by their local environment. Tregs in these tissues can employ a wide variety of mechanisms to accumulate and acquire tissue-specific function, including conversion from conventional T cells, canonical T cell receptor (TCR)-dependent expansion and non-canonical, TCR-independent, cytokine-dependent expansion. Intriguingly, the niche-specific function of tissue Tregs can be independent of, and mutually exclusive of, their immunosuppressive capacity. Together, this recent literature reveals that Tregs can accumulate in discrete tissue sites through non-canonical mechanisms, and in response to niche-specific cues can acquire distinct functions, which distinguish them from their peripheral, lymphoid Treg counterparts. Other tissue Treg populations remain to be identified and characterized. Moreover, it is unknown whether other tissue Tregs rely on non-canonical mechanisms of accumulation, and exhibit functions distinct from the typical Treg immunosuppressive role. Tregs are known to accumulate in the CNS during infection, injury and inflammation. The CNS is an organ with distinctive architecture that maintains a regulated interaction with the peripheral immune system due to its critical function and poor regenerative capacity. While it is known that Tregs broadly protect against excessive tissue pathology in the diseased CNS, the origin, localization, function, mechanism of accumulation, and gene signature of CNS-infiltrating Tregs have not been studied, likely due to the challenge of isolating these rare cells and distinguishing them from circulating cells left over after perfusion. Here, we establish a safe model of CNS infection using encephalomyocarditis virus and employ a series of methods to locate, monitor and isolate CNS-infiltrating Tregs free from contamination from the circulation. We show that a distinct population of thymus-derived Tregs accumulates within the cerebrospinal fluid (CSF) of the EMCV-infected CNS, independently of lymph node priming. Tregs function in this unique niche to limit excessive tissue pathology. While CNS Tregs maintain expression of core Treg signature genes, including FoxP3, their global transcriptome is more similar to that of conventional T cells (Tcons) harvested from the infected CNS than to that of peripheral Tregs. Bioinformatics analysis reveals that genes shared by CNS Tcons and CNS Tregs are also shared by Tregs and Tcons from injured muscle and from the visceral adipose tissue of aged mice, indicating that tissue inflammation and injury, rather than viral infection per se, contribute to CNS Treg accumulation, function and phenotype. Additionally, we observe that CNS Treg accumulation during infection is associated with a simultaneous increase in meningeal/choroid plexus dendritic cells (m/chDCs), which are professional antigen presenting cells that localize to the gates of the CNS. Splenic cDC and peripheral lymphoid Treg homeostasis are linked, and both populations can be artificially increased by treatment with the DC-poietin and adjuvant, Ftlt3L. Therefore, we hypothesized that CNS Tregs and m/chDCs may also be linked and could also be manipulated by Flt3L treatment. Indeed, treatment with Flt3L in conjunction with EMCV infection results in enhanced CNS Treg and m/chDC accumulation, independent of Flt3 receptor expression on Tregs. In an effort to determine if dendritic cells mediate CNS Treg increase during infection, we turned to a DC-ablative mouse model in which all CD11c-expressing cells express the catalytic subunit of diphtheria toxin and are depleted. Surprisingly, while splenic cDCs are completely abrogated in these mice, a portion of m/chDCs persists, unaffected. Moreover, CNS Tregs accumulate normally in these mice during infection. This data suggests an unappreciated heterogeneity in m/chDCs, and indicates that those that remain unaffected in these mice may mediate CNS Treg accumulation during infection. While characterizing m/chDC heterogeneity, we found that m/chDCs comprise three distinct subsets with unknown potential. Whereas m/chDCs were previously considered to be a homogeneous, CD45hiB220-CD11c+MHCII+ population, we have found them to contain three subsets, distinguishable by IRF8 and FcR-γ expression. This finding paves the way for further study of the origin, localization, and division of labor between these three m/chDC subsets. In summary, our studies clarify the distinct compartmentalization, lymph node-independent accumulation, and inflammation-associated gene signature of CNS Tregs. Most importantly, these findings have implications for neuro-immune cross-talk, particularly at the interface of the CSF and brain parenchyma. That is, neural progenitors extend their apical domains into the CSF of the ventricles, and therefore may be subject to regulation by CSF-borne Tregs. Further, while many studies have focused on the differences between tissue Treg subsets, we find a core set of genes expressed by CNS Tregs, injured muscle Tregs and VAT Tregs. This data suggests that common mechanisms may be used for therapeutic manipulation of these cells.