Due to a lack of data in regard to the spread of viral infections in Polish pigeon populations, studies were undertaken to assess the frequency of adeno-, circo- and herpesvirus infections in flocks of pigeons across the entire country. In total, 107 flocks were examined, of which 61 per cent consisted of racing and 39 per cent of fancy pigeons. The flocks were divided into groups according to breed (racing and fancy pigeons) as well as physical condition (healthy and sick). In the studied pigeon flocks, the pigeon circovirus (PiCV) genetic material was the most frequently detected (44.5-100 per cent depending on the group), pigeon herpesvirus genetic material was second in frequency (0-30 per cent depending on the group), while genetic material of pigeon adenovirus was found only in two flocks of young birds with clinical symptoms of Young Pigeon Disease Syndrome (YPDS). The presence of fowl adenovirus (FAdV) genetic material was not detected in any of the studied flocks. Results obtained demonstrate a wide spread of circovirus in pigeon flocks in Poland, and substantiate earlier theories proposed by other authors, that immunosuppression evoked by PiCV infection is one of the main causative agents of YPDS.
We hypothesized that cytokines influence luteal angiogenesis in mares, while angiogenic factors themselves can also regulate luteal secretory capacity. Therefore, the purpose of this study was to evaluate the role of cytokines--tumor necrosis factor alpha (TNF), interferon gamma (IFNG) and Fas ligand (FASL)--on in vitro modulation of angiogenic activity and mRNA level of vascular endothelial growth factor A (VEGF), its receptor VEGFR2, thrombospondin 1 (TSP1), and its receptor CD36 in equine corpus luteum (CL) throughout the luteal phase. After treatment, VEGF protein expression was determined in midluteal phase (mid) CL cells. The role of VEGF on regulation of luteal secretory capacity was assessed by progesterone (P(4)) and prostaglandin E(2) (PGE(2)) production and by mRNA levels for steroidogenic enzymes 3-beta-hydroxysteroid dehydrogenase (3betaHSD) and PGE synthase (PGES). In early CL cells, TNF increased angiogenic activity (bovine aortic endothelial cell viability) and VEGF and VEGFR2 mRNA levels and decreased CD36 (real-time PCR relative quantification). In mid-CL cells, TNF increased VEGF mRNA and protein expression (Western blot analysis) and reduced CD36 mRNA levels, while FASL and TNF+IFNG+FASL decreased VEGF protein expression. In late CL cells, TNF and TNF+IFNG+FASL reduced VEGFR2 mRNA, but TNF+IFNG+FASL increased TSP1 and CD36 mRNA. VEGF treatment increased mRNA levels of 3betaHSD and PGES and secretion of P(4) and PGE(2). In conclusion, these findings suggest a novel auto/paracrine action of cytokines, specifically TNF, on the up-regulation of VEGF for angiogenesis stimulation in equine early CL, while at luteolysis, cytokines down-regulated angiogenesis. Additionally, VEGF stimulated P(4) and PGE(2) production, which may be crucial for CL establishment.
BackgroundAvian Metapneumovirus (aMPV) infections are a huge economical issue for the poultry industry worldwide. Although maternal antibodies do not protect turkey poults against turkey rhinotracheitis (TRT), almost no studies have been conducted so far regarding the impact of these antibodies on vaccine induced immunity development against aMPV infection. We conducted four experiments on commercial turkeys aimed at comparing local humoral and cell mediated immune response of maternally delivered anti-aMPV antibody positive (MDA+; Experiment I and II) and negative (MDA-; Experiment III and IV) turkeys following vaccination with an attenuated live aMPV subtype A vaccine at the day of hatch (Experiment I and III) or at two weeks of age (Experiment II and IV).ResultsRegardless of the birds’ age, vaccination of MDA- turkeys resulted in strong stimulation of CD8+ T lymphocytes in the Harderian gland and tracheal mucosa, whereas vaccination of MDA+ birds stimulated mainly CD4+ T cells in those structures. An increase in the level of anti-aMPV IgY antibodies was noted in the serum (but not in tracheal washings) as early as 7 days after vaccination, but only in birds possessing low levels (MDA+ birds vaccinated at 2 weeks of age) or no maternal anti-aMPV antibodies at the time of vaccination. In MDA+ turkeys vaccinated at hatch, the decrease in serum levels of maternal anti-aMPV antibodies proceeded faster (in comparison to control group), which, together with faster viral clearance, indicates that maternal antibodies can inhibit vaccine virus replication and influence the development of vaccine-induced immunity.ConclusionThis study provides the first documented evidence that the frequency of TRT outbreaks in the field and/or failure of TRT vaccination could be correlated with differences in the immunological status and/or age of vaccinated turkeys.
The aim of the study was to determine the effect of a Polish low-virulence isolate of haemorrhagic enteritis adenovirus (HEV) on the immune system in turkeys and on the course of colibacillosis in birds infected under laboratory conditions. Turkeys were infected per os with HEV at the dose of
The aim of this study was to evaluate the serologic status of domestic pigeons not infected and asymptomatically infected with the pigeon circovirus (PiCV) with the use of an enzyme-linked assay based on PiCV recombinant capsid protein as a plate antigen. Recombinant PiCV capsid protein was produced by transforming E. coli BL21 (DE3) Rosetta colonies with expression plasmids.Blood samples and cloacal swabs were collected from 171 asymptomatic pigeons. The birds were divided into two groups (infected and not infected with PiCV) based on the results of Sybr Green real time PCR screening for the presence of PiCV genetic material. Approximately 70% of the pigeons tested positive for anti-PiCV antibodies regardless of their infection status. Antibody levels, the coefficient of variation and standard deviation were significantly higher in the group of infected pigeons.The results indicate that ELISA is a highly useful test that complements molecular methods in evaluations of PiCV infection status in domestic pigeons. The spread of pigeon circovirus infections can be controlled by keeping breeding flocks free of PiCV, which can only be achieved by subjecting birds to real time PCR and serological tests.
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