RESUMO
It is known that growth hormone (GH) is expressed in immune cells, where it exerts immunomodulatory effects. However, the mechanisms of expression and release of GH in the immune system remain unclear. We analyzed the effect of growth hormone-releasing hormone (GHRH), thyrotropin-releasing hormone (TRH), ghrelin (GHRL), and somatostatin (SST) upon GH mRNA expression, intracellular and released GH, Ser133-phosphorylation of CREB (pCREBS133), intracellular Ca2+ levels, as well as B-cell activating factor (BAFF) mRNA expression in bursal B-lymphocytes (BBLs) cell cultures since several GH secretagogues, as well as their corresponding receptors (-R), are expressed in B-lymphocytes of several species. The expression of TRH/TRH-R, ghrelin/GHS-R1a, and SST/SST-Rs (Subtypes 1 to 5) was observed in BBLs by RT-PCR and immunocytochemistry (ICC), whereas GHRH/GHRH-R were absent in these cells. We found that TRH treatment significantly increased local GH mRNA expression and CREB phosphorylation. Conversely, SST decreased GH mRNA expression. Additionally, when added together, SST prevented TRH-induced GH mRNA expression, but no changes were observed in pCREBS133 levels. Furthermore, TRH stimulated GH release to the culture media, while SST increased the intracellular content of this hormone. Interestingly, SST inhibited TRH-induced GH release in a dose-dependent manner. The coaddition of TRH and SST decreased the intracellular content of GH. After 10 min. of incubation with either TRH or SST, the intracellular calcium levels significantly decreased, but they were increased at 60 min. However, the combined treatment with both peptides maintained the Ca2+ levels reduced up to 60-min. of incubation. On the other hand, BAFF cytokine mRNA expression was significantly increased by TRH administration. Altogether, our results suggest that TRH and SST are implicated in the regulation of GH expression and release in BBL cultures, which also involve changes in pCREBS133 and intracellular Ca2+ concentration. It is likely that TRH, SST, and GH exert autocrine/paracrine immunomodulatory actions and participate in the maturation of chicken BBLs.
Assuntos
Proteínas Aviárias/imunologia , Linfócitos B/imunologia , Bolsa de Fabricius/imunologia , Galinhas/imunologia , Grelina/imunologia , Hormônio Liberador de Hormônio do Crescimento/imunologia , Hormônio do Crescimento/imunologia , Somatostatina/imunologia , Hormônio Liberador de Tireotropina/imunologia , Animais , Linfócitos B/citologia , Bolsa de Fabricius/citologia , Técnicas de Cultura de Células , Células CultivadasRESUMO
DNA methylation is an important epigenetic modification in eukaryotes, which plays a significant role in regulating gene expression. When the host is invaded by the influenza virus, gene expression is regulated via changes in DNA methylation levels or patterns, leading to the activation or suppression of relevant signaling pathways or networks, triggering a series of immune responses against viral invasion. Here, we investigated the changes in genomic DNA methylation in the immune organs of chicken infected with H5N1 influenza virus. Genome-wide DNA methylation levels in the spleen, thymus, and bursa of Fabricius of specific pathogen-free (SPF) chicken infected with the Guangdong (G-H5N1) and Anhui (A-H5N1) H5N1 strains, and water (control) were analyzed by fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP). The results indicated that total DNA methylation levels did not differ between spleen genomic DNA in chicken treated with different viral strains and the control (P > 0.05). However, the total DNA methylation levels were significantly upregulated in the thymus (P < 0.01) and bursa (P < 0.05) of chicken in the A-H5N1 group compared to those in the G-H5N1 and control groups. These results provide a basis for the screening of avian influenza-resistance genes or methylation markers, analyzing the epigenetic regulation mechanisms of avian influenza, and performing selective breeding for disease resistance.
Assuntos
Metilação de DNA/genética , Resistência à Doença/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/genética , Animais , Bolsa de Fabricius/imunologia , Bolsa de Fabricius/virologia , Galinhas , Metilação de DNA/imunologia , Resistência à Doença/imunologia , Epigênese Genética , Genoma/genética , Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/imunologia , Influenza Aviária/virologia , Transdução de Sinais , Baço/imunologia , Baço/virologia , Timo/imunologia , Timo/virologiaRESUMO
Infection of poultry with chicken anemia virus (CAV) is implicated in several field problems in broiler flocks due to the immunosuppression generated and, consequently, the increased susceptibility to secondary infections. Recently, we have reported an increased occurrence of clinical cases caused by CAV strains distantly related to those commonly used for vaccination. In order to understand the behavior of two Argentinean CAV strains (CAV-10 and CAV-18) in two-week-old chickens, an immune and histopathological study was performed. Neither mortality nor clinical signs were observed in the infected or control groups. Thymus lobes from chickens infected with both CAV viruses were smaller compared to the negative control group. At 14 days post-infection (dpi), only chickens inoculated with CAV-10 show a severe depletion of lymphocytes in the thymus cortex and in follicles from the bursa of Fabricius. Also thymopoiesis disorders, such as reduction in the percentage of total DP (CD4 + CD8α+) thymocytes and alteration in the percentages of DP subpopulations, were more important in animals inoculated with the CAV-10 than the CAV-18 strain. In addition, only animals infected with CAV-10 show a decrease in CD8αß splenocytes. Altogether our results show that, although both Argentinean CAV strains produce subclinical infections in chickens causing immunosuppression at 14 dpi, they might differ in their in vivo pathogenicity.
Assuntos
Vírus da Anemia da Galinha/fisiologia , Galinhas , Infecções por Circoviridae/veterinária , Genoma Viral , Doenças das Aves Domésticas/virologia , Subpopulações de Linfócitos T/metabolismo , Animais , Argentina , Infecções Assintomáticas , Bolsa de Fabricius/imunologia , Bolsa de Fabricius/virologia , Vírus da Anemia da Galinha/genética , Vírus da Anemia da Galinha/imunologia , Infecções por Circoviridae/imunologia , Infecções por Circoviridae/patologia , Tolerância Imunológica , Dados de Sequência Molecular , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/patologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Baço/imunologia , Baço/virologia , Timo/imunologia , Timo/virologiaRESUMO
Infectious bursal disesase is a highly contagious, wide spread immunosuppressive chicken disease caused by the Infectious Bursal Disease Virus (IBDV). IBDV is a two segmented double-strand RNA virus, member of the Birnaviridae family. In order to study the interaction between IBDV and the immune system, chickens were exposed to an intermediate IBDV strain by intramuscular route, and using Real Time PCR the expression of a panel of avian cytokines and chemokines in duodenum, spleen and bursa of Fabricius was analyzed. Also, splenic nitrite (NO2) production and the frequencies of different mononuclear cell populations were evaluated by Griess reaction and flow cytometry, respectively. Intramuscular (i.m.) IBDV inoculation promoted an over expression of proinflammatory cytokines IL-6, IL-15 and gIFN in spleen, which correlated with an increase of gIFN plasma concentration measured by ELISA, together with an increment of NO2 concentration in splenocyte supernatants at 1dpi. Results obtained in the present work showed that IBDV of intermediate virulence, given i.m., induced similar effects to those previously described for highly virulent IBDV in early innate immune responses. Considering that the i.m. route is the route of choice for the delivery of new generation vaccines, and that the use of recombinant antigens also requires the addition of adjuvants for proper immune stimulation, results presented here could contribute to identify suitable cytokines to be used or to be stimulated when utilizing subunit vaccines, for the improvement of prevention tools for avian health.
Assuntos
Imunidade Adaptativa , Infecções por Birnaviridae/prevenção & controle , Galinhas/imunologia , Imunidade Inata , Vírus da Doença Infecciosa da Bursa/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinação/métodos , Animais , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Bolsa de Fabricius/imunologia , Bolsa de Fabricius/virologia , Galinhas/virologia , Ensaio de Imunoadsorção Enzimática/veterinária , Citometria de Fluxo , Vírus da Doença Infecciosa da Bursa/patogenicidade , Injeções Intramusculares , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-15/biossíntese , Interleucina-15/imunologia , Interleucina-6/biossíntese , Interleucina-6/imunologia , Nitritos/análise , Reação em Cadeia da Polimerase/veterinária , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Baço/imunologia , Baço/virologia , Vacinas Virais/imunologiaRESUMO
Expression of growth hormone (GH) and GH receptor (GHR) genes in the bursa of Fabricius of chickens suggests that it is an autocrine/paracrine site of GH production and action. The cellular localization of GH and GH mRNA within the bursa was the focus of this study. GH mRNA was expressed mainly in the cortex, comprised of lymphocyte progenitor cells, but was lacking in the medulla where lymphocytes mature. In contrast, more GH immunoreactivity (GH-IR) was present in the medulla than in the cortex. In non-stromal tissues, GH-IR and GH mRNA were primarily in lymphocytes, and also in macrophage-like cells and secretory dendritic cells. In stromal tissues, GH mRNA, GH and GHR were expressed in cells near the connective tissue (CT) between follicles and below the outer serosa. In contrast, GH (but not GH mRNA or GHR), was present in cells of the interfollicular epithelium (IFE), the follicle-associated epithelium (FAE) and the interstitial corticoepithelium. This mismatch may reflect dynamic temporal changes in GH translation. Co-expression of GHR-IR, GH-IR, GH mRNA and IgG was found in immature lymphoid cells near the cortex and in IgG-IR CT cells, suggesting an autocrine/paracrine role for bursal GH in B-cell differentiation.
Assuntos
Bolsa de Fabricius/imunologia , Galinhas/imunologia , Galinhas/metabolismo , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Hormônio do Crescimento/genética , Hormônio do Crescimento/imunologia , Animais , Bolsa de Fabricius/metabolismo , Galinhas/genética , Hormônio do Crescimento/metabolismo , Imunoglobulina G/imunologia , RNA Mensageiro/genética , Receptores da Somatotropina/metabolismoRESUMO
This study aimed to evaluate the effect of dietary ochratoxin, in the presence or absence of aluminosilicate, on the histology of the bursa of Fabricius, liver and kidneys, and on the humoral immune response of broilers vaccinated against Newcastle disease virus. The exposure of birds to 2 p.p.m. ochratoxin, in the presence or absence of aluminosilicate, reduced their humoral immune response and the number of mitotic cells in the bursa. The relative weight of the livers of the birds exposed to this toxin was increased and, microscopically, there was hepatocyte vacuolation and megalocytosis with accompanying hyperplasia of the biliary epithelium. The kidneys showed hypertrophy of the renal proximal tubular epithelium, with thickening of the glomerular basement membrane. Aluminosilicate did not ameliorate the deleterious effects of the ochratoxin.
Assuntos
Silicatos de Alumínio/uso terapêutico , Galinhas/imunologia , Ocratoxinas/antagonistas & inibidores , Ocratoxinas/toxicidade , Doenças das Aves Domésticas/induzido quimicamente , Doenças das Aves Domésticas/imunologia , Animais , Bolsa de Fabricius/efeitos dos fármacos , Bolsa de Fabricius/imunologia , Bolsa de Fabricius/patologia , Contagem de Células , Interações Medicamentosas , Feminino , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Vírus da Doença de Newcastle/imunologia , Tamanho do Órgão , Doenças das Aves Domésticas/tratamento farmacológico , Doenças das Aves Domésticas/patologia , Vacinas Virais/imunologiaRESUMO
Las células del sistema inmune que incluyen linfocitos, granulocitos y monocitos-macrófagos, se forman en la médula ósea a partir de células pluripotentes, a través de un proceso finamente regulado y el que participan varias citoquinas. Los granulocitos (neutrófilos, eosinófilos y basófilos) presentan particularidades morfológicas y funcionales. La principal función de los neutrófilos es su capacidad fagocítica. En el capítulo se explican los procesos de activación, quimiotaxis, fagocitosis y bacteriolisis. Las células del sistema fagocítico mononuclear (monocitos y macrófagos) tienen como función fagocitar; actividad más desarrollada en los macrófagos, que son células tisulares derivadas de los monocitos circulantes. Los linfocitos son las células que participan en la inmunidad adquirida o específica. Las células T participan en la inmunidad celular y las células B en la inmunidad humoral. Una tercera subpoblación de linfocitos, las células NK, participan en la inmunidad celular de tipo innata. Los órganos linfoides se pueden clasificar en primarios (timo y médula ósea) y secundarios (bazo, ganglios linfáticos y tejido linfoide asociado a mucosas). En el timo maduran los LT y en la médula ósea los LB. En los órganos linfoides secundarios los linfocitos y otras células del sistema inmune toman contacto con los antígenos y es en ellos donde se genera la respuesta inmune específica. En estos órganos existen zonas ricas en células T, y otras en que, principalmente, existen células B. La capacidad de los linfocitos de recircular entre los órganos linfoides secundarios, vasos linfáticos, conducto torácico y vasos sanguíneos le permiten tomar contacto con antígenos en diferentes lugares del organismo
Assuntos
Humanos , Sistema Imunitário/anatomia & histologia , Sistema Imunitário/fisiologia , Basófilos/imunologia , Bolsa de Fabricius/imunologia , Eosinófilos/imunologia , Granulócitos/imunologia , Leucopoese/fisiologia , Tecido Linfoide/imunologia , Macrófagos/imunologia , Monócitos/imunologia , Fagócitos/imunologia , Sistema Linfático/imunologia , Timo/imunologiaRESUMO
Programmed cell death, or apoptosis, is involved in the normal physiology of many immunocompetent organs, including lymphocytes of the bursa of Fabricius in chickens. Involvement of apoptosis has also been described in some viral diseases such as AIDS. The purpose of this work was to study the potential role of apoptosis in the pathogenesis of Gumboro disease in the bursa of Fabricius. Our results show that 1-3 days after infection of young chickens with infectious bursal disease virus, the number of apoptotic cells increases and cellularity and proliferation decrease. Because of the dynamic nature of bursal lymphocyte populations and the involvement of apoptosis in lymphocyte cell physiology, the increased level of cells undergoing apoptosis may be due to an impairment in the withdrawal of apoptotic cells. A concomitant increase in macrophages in infected bursae and a dramatic decrease in cellularity suggest that an increase in apoptosis may be an important cause of cell depletion.
Assuntos
Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/patologia , Bolsa de Fabricius/patologia , Vírus da Doença Infecciosa da Bursa , Ativação Linfocitária , Linfócitos/imunologia , Animais , Apoptose , Bolsa de Fabricius/imunologia , Ciclo Celular , Galinhas , DNA/análise , Citometria de Fluxo/métodos , Linfócitos/patologia , Fatores de TempoRESUMO
The cloacal bursa is a primary lymphoid organ responsible for the maturation of B-lymphocytes. It has been suggested that the bursa may also play a peripheral role when antigens are inoculated by cloacal route. Qualitative and quantitative structural modifications in the bursa from chicks inoculated with Bordetella pertussis by the cloacal route were investigated. Observations indicated that the relative bursal growth as well as the volume fraction and the mitotic index of the follicular medulla from experimental bursae are significantly greater than those of the controls. Macrophages which have phagocytized bacteria, and a gradual relative increase of the RER of lymphoblasts, were other structural modifications found exclusively in the follicular medulla. The observations suggest that the bursal follicular cortex and medulla act as autonomous histophysiological compartments, the latter being responsible for an antigenic stimulation when Bordetella pertussis is intracloacally inoculated in chicks.