RESUMO
The rapid development of potency assays is critical in the development of life-saving vaccines. The traditional plaque assay or fifty percent tissue culture infectious dose (TCID50) assay used to measure the potency of live virus vaccines is time consuming, labor intensive, low throughput and with high variability. Described here is the development and qualification of a cell-based reporter potency assay for two vaccines for respiratory viral infection, one based on the recombinant vesicular stomatitis virus (rVSV) backbone, termed Vaccine 1 in this paper, and the other based on the measles virus vector, termed Vaccine 2. The reporter potency assay used a Vero E6 cell line engineered to constitutively express NanuLuc® luciferase, termed the VeroE6-NLuc or JM-1 cell line. Infection of JM-1 cells by a live virus, such as rVSV or measles virus, causes a cytopathic effect (CPE) and release of NanuLuc® from the cytoplasm into the supernatant, the amount of which reflects the intensity of the viral infection. The relative potency was calculated by comparison to a reference standard using parallel line analysis (PLA) in a log-log linear model. The reporter assay demonstrated good linearity, accuracy, and precision, and is therefore suitable for a vaccine potency assay. Further evaluation of the Vaccine 1 reporter assay demonstrated the robustness to a range of deliberate variation of the selected assay parameters and correlation with the plaque assay. In conclusion, we have demonstrated that the reporter assay using the JM-1 cell line could be used as a potency assay to support the manufacturing and release of multiple live virus vaccines.
RESUMO
Advances in anti-retroviral therapy over the last two decades have allowed life expectancy in patients infected with the human immunodeficiency virus to approach that of the general population. The process of aging in mammalian species, including rats, results in immune response changes, alterations in immunological phenotypes, and ultimately increased susceptibility to many infectious diseases. In order to investigate the immunological pathologies associated with chronic HIV-1 disease, particularly in aging individuals, the HIV-1 transgenic (HIV-1Tg) rat model was utilized. HIV-1Tg rats were challenged with lipopolysaccharide (LPS) to determine immunological alterations during the aging process. LPS is known to cause an imbalance in cytokine and chemokine release, and provides a method to identify changes in immune responses to bacterial infection in an HIV animal model. An immune profile and accompanying cellular consequences as well as changes in inflammatory cytokine and chemokine release related to age and genotype were assessed in HIV-1Tg rats. The percentage of T cells decreased with age, particularly T cytotoxic cells, whereas T helper cells increased with age. Neutrophils and monocytes increased in HIV-1Tg rats during maturation compared to age-matched F344 control rats. Aging HIV-1Tg rats displayed a significant increase in the pro-inflammatory cytokines, IL-6 and TNF-α, along with an increase in the chemokine, KC/GRO, in comparison to age-matched controls. Our data indicate that immunophenotype and immune responses can change during aging in HIV-positive individuals. This information could be important in determining the most beneficial age-dependent therapeutic treatment for HIV patients.
Assuntos
Envelhecimento/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Animais , Quimiocinas/sangue , Infecções por HIV/sangue , Infecções por HIV/tratamento farmacológico , Lipopolissacarídeos/farmacologia , Linfonodos/imunologia , Linfonodos/metabolismo , Masculino , Fenótipo , Ratos Endogâmicos F344 , Ratos Transgênicos , Baço/imunologia , Baço/patologia , Linfócitos T/imunologia , Linfócitos T/virologiaRESUMO
The health and disease-related biology of the CXCR4 chemokine receptor presents the challenge of finding a small molecule that can bind CXCR4 and block T-cell tropic human immunodeficiency virus type 1 (HIV-1) cell entry, while preserving the ability of CXCR4 to respond to its native ligand, CXCL12. HIV entry into the host cell involves the interaction of the viral envelope glycoprotein gp120 binding to CD4, followed by a rearrangement in gp120, and subsequent interaction with the chemokine receptor CXCR4 or CCR5. These initial events can be re-created in a cell fusion assay that represents a surrogate system, mimicking the early stages of viral entry via these host cell receptors. In the current study, a T-tropic HIV cell fusion assay was established using U2OS cells expressing the envelope glycoprotein gp160 from the T-tropic HIV NL4-3 and HeLa cells expressing CD4 and CXCR4. Detection of the cell fusion event was based on a Gal4/VP16-activated ß-lactamase signal and was measured by automated microscopy or laser scanning plate cytometry. Changes in morphology associated with cell fusion were combined with ß-lactamase activity to generate results with robust assay statistics in both 384-well and 1536-well plates. Compounds were subsequently characterized by CXCR4 signaling assays to eliminate functional antagonists and allow the identification of a function-sparing HIV entry inhibitor.
Assuntos
Inibidores da Fusão de HIV/farmacologia , Testes de Sensibilidade Microbiana/métodos , Fenótipo , Receptores CXCR4/metabolismo , Internalização do Vírus/efeitos dos fármacos , Linhagem Celular , Expressão Gênica , Genes Reporter , Ensaios de Triagem em Larga Escala , Humanos , Receptores CXCR4/genética , Proteínas Recombinantes de Fusão , Reprodutibilidade dos TestesRESUMO
Megakaryocytes, which mature from hematopoietic progenitors in the bone marrow, further differentiate by reorganizing their cytoplasm into long proplatelet extensions that release platelets into the circulation. The molecular mechanisms underlying this highly dynamic cytoplasmic and cytoskeletal remodeling process are only poorly understood. Here we report that sphingosine 1-phosphate receptor 4 (S1P(4)) is specifically up-regulated during the development of human megakaryocytes from progenitor cells and is expressed in mature murine megakaryocytes. Megakaryocytes generated from S1P(4)-deficient murine bone marrow showed atypical and reduced formation of proplatelets in vitro. The recovery of platelet numbers after experimental thrombocytopenia was significantly delayed in S1p4(-/-) mice. Remarkably, overexpression and stimulation of S1P(4) in human erythroleukemia HEL cells promoted endomitosis, formation of cytoplasmic extensions, and subsequent release of platelet-like particles. These observations indicate that S1P(4) is involved in shaping the terminal differentiation of megakaryocytes.
Assuntos
Plaquetas/citologia , Diferenciação Celular/fisiologia , Megacariócitos/citologia , Megacariócitos/metabolismo , Receptores de Lisoesfingolipídeo/metabolismo , Animais , Southern Blotting , Western Blotting , Células da Medula Óssea/citologia , Diferenciação Celular/genética , Linhagem Celular , Células Cultivadas , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Receptores de Lisoesfingolipídeo/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Trombocitopenia/genética , Trombocitopenia/metabolismo , Trombocitopenia/patologia , Trombopoetina/sangueRESUMO
G protein-coupled receptor 119 (GPR119) is expressed in pancreatic islets and intestine, and is involved in insulin and incretin hormone release. GPR119-knockout (Gpr119(-/-)) mice were reported to have normal islet morphology and normal size, body weight (BW), and fed/fasted glucose levels. However, the physiological function of GPR119 and its role in maintaining glucose homeostasis under metabolic stress remain unknown. Here, we report the phenotypes of an independently generated line of Gpr119(-/-) mice under basal and high-fat diet (HFD)-induced obesity. Under low-fat diet feeding, Gpr119(-/-) mice show normal plasma glucose and lipids, but have lower BWs and lower post-prandial levels of active glucagon-like peptide 1 (GLP-1). Nutrient-stimulated GLP-1 release is attenuated in Gpr119(-/-) mice, suggesting that GPR119 plays a role in physiological regulation of GLP-1 secretion. Under HFD-feeding, both Gpr119(+)(/)(+) and Gpr119(-/-) mice gain weight similarly, develop hyperinsulinemia and hyperleptinemia, but not hyperglycemia or dyslipidemia. Glucose and insulin tolerance tests did not reveal a genotypic difference. These data show that GPR119 is not essential for the maintenance of glucose homeostasis. Moreover, we found that oleoylethanolamide (OEA), reported as a ligand for GPR119, was able to suppress food intake in both Gpr119(+)(/)(+) and Gpr119(-/-) mice, indicating that GPR119 is not required for the hypophagic effect of OEA. Our results demonstrate that GPR119 is important for incretin and insulin secretion, but not for appetite suppression.
Assuntos
Peptídeo 1 Semelhante ao Glucagon/metabolismo , Homeostase/genética , Redes e Vias Metabólicas/genética , Receptores Acoplados a Proteínas G/fisiologia , Via Secretória/genética , Animais , Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/genética , Células Cultivadas , Endocanabinoides , Feminino , Marcação de Genes , Glucose/metabolismo , Homeostase/efeitos dos fármacos , Incretinas/metabolismo , Incretinas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Lisofosfatidilcolinas/metabolismo , Lisofosfatidilcolinas/farmacologia , Masculino , Redes e Vias Metabólicas/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ácidos Oleicos/metabolismo , Ácidos Oleicos/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/metabolismo , Via Secretória/efeitos dos fármacosRESUMO
Neuromedin U (Nmu) is a neuropeptide expressed primarily in the gastrointestinal tract and central nervous system. Previous reports have identified two G protein-coupled receptors (designated Nmur1 and Nmur2) that bind Nmu. Recent reports suggest that Nmu mediates immune responses involving mast cells, and Nmur1 has been proposed to mediate these responses. In this study, we generated mice with an Nmur1 deletion and then profiled the responses of these mice in a cutaneous inflammation model utilizing complete Freund's adjuvant (CFA). We report here that mice lacking Nmur1 had normal inflammation responses with moderate changes in serum cytokines compared to Nmur1(+/+) littermates. Although differences in IL-6 were observed in mice lacking Nmu peptide, these mice exhibited a normal response to CFA. Our data argues against a major role for Nmur1 in mediating the reported inflammatory functions of NmU.
Assuntos
Dermatite/imunologia , Receptores de Neurotransmissores/fisiologia , Animais , Citocinas/sangue , Dermatite/genética , Adjuvante de Freund/imunologia , Adjuvante de Freund/farmacologia , Deleção de Genes , Camundongos , Camundongos Knockout , Receptores de Neurotransmissores/genéticaRESUMO
OBJECTIVE: FFAR1/GPR40 is a G-protein-coupled receptor expressed predominantly in pancreatic islets mediating free fatty acid-induced insulin secretion. However, the physiological role of FFAR1 remains controversial. It was previously reported that FFAR1 knockout (Ffar1(-/-)) mice were resistant to high-fat diet-induced hyperinuslinemia, hyperglycemia, hypertriglyceridemia, and hepatic steatosis. A more recent report suggested that although FFAR1 was necessary for fatty acid-induced insulin secretion in vivo, deletion of FFAR1 did not protect pancreatic islets against fatty acid-induced islet dysfunction. This study is designed to investigate FFAR1 function in vivo using a third line of independently generated Ffar1(-/-) mice in the C57BL/6 background. RESEARCH DESIGN AND METHODS: We used CL-316,243, a beta3 adrenergic receptor agonist, to acutely elevate blood free fatty acids and to study its effect on insulin secretion in vivo. Ffar1(+/+) (wild-type) and Ffar1(-/-) (knockout) mice were placed on two distinct high-fat diets to study their response to diet-induced obesity. RESULTS: Insulin secretion was reduced by approximately 50% in Ffar1(-/-) mice, confirming that FFAR1 contributes significantly to fatty acid stimulation of insulin secretion in vivo. However, Ffar1(+/+) and Ffar1(-/-) mice had similar weight, adiposity, and hyperinsulinemia on high-fat diets, and Ffar1(-/-) mice showed no improvement in glucose or insulin tolerance tests. In addition, high-fat diet induced comparable levels of lipid accumulation in livers of Ffar1(+/+) and Ffar1(-/-) mice. CONCLUSIONS: FFAR1 is required for normal insulin secretion in response to fatty acids; however, Ffar1(-/-) mice are not protected from high-fat diet-induced insulin resistance or hepatic steatosis.
Assuntos
Gorduras na Dieta/administração & dosagem , Doenças Metabólicas/fisiopatologia , Receptores Acoplados a Proteínas G/fisiologia , Adiposidade , Animais , Peso Corporal/fisiologia , Teste de Tolerância a Glucose , Hiperinsulinismo/fisiopatologia , Insulina/metabolismo , Doenças Metabólicas/etiologia , Doenças Metabólicas/genética , Camundongos , Camundongos Knockout , Receptores Acoplados a Proteínas G/genéticaRESUMO
The Gpbar1 [G-protein-coupled BA (bile acid) receptor 1] is a recently identified cell-surface receptor that can bind and is activated by BAs, but its physiological role is unclear. Using targeted deletion of the Gpbar1 gene in mice, we show that the gene plays a critical role in the maintenance of bile lipid homoeostasis. Mice lacking Gpbar1 expression were viable, developed normally and did not show significant difference in the levels of cholesterol, BAs or any other bile constituents. However, they did not form cholesterol gallstones when fed a cholic acid-containing high-fat diet, and liver-specific gene expression indicated that Gpbar1-deficient mice have altered feedback regulation of BA synthesis. These results suggest that Gpbar1 plays a critical role in the formation of gallstones, possibly via a regulatory mechanism involving the cholesterol 7alpha-hydroxylase pathway.