•A characteristic Th2 response was observed in the jejunum of A. galli-infected.•Increased expression of IFN-γ, IL-10, and TGF-β4 was found in the spleen at day 7.•Decreased expression of jejunal ...IFN-γ and IL-13 was found at day 10.•From day 14 decreased expression of IFN-γ and TGF-β4 in spleen, IFN-γ in jejunum, and decreased expression of IFN-γ and IL-10 in caecal tonsils were found.
In the poultry production industry, chickens with access to outdoor areas are exposed to a wide range of parasites e.g. the helminth Ascaridia galli. By real-time quantitative RT-PCR, the relative gene expression of the T helper 1 (Th1) cytokine IFN-γ, the T helper 2 (Th2) cytokine IL-13, the anti-inflammatory cytokines IL-10 and TGF-β4 and the pro-inflammatory cytokine IL-17F were determined over a period of 3 weeks in A. galli and non-A. galli-infected chickens. A characteristic Th2 response was observed in the jejunum of A. galli-infected chickens with increased expression of IL-13 and decreased expression of IFN-γ from day 14 post infection. At the putative time of larvae invasion into the intestinal mucosa (day 7), an increased expression of IFN-γ, IL-10, and TGF-β4 was observed in the spleen. At the putative onset of the innate immune response (day 10), a decreased expression of jejunal IFN-γ and IL-13 was observed. Finally, at the expected period of an adaptive immune response (days 14–21) a general decreased expression of IFN-γ and TGF-β4 in spleen and IFN-γ in jejunum was followed by a decreased expression of IFN-γ and IL-10 at day 21 in caecal tonsils.
Dopamine, a catecholamine neurotransmitter, is important for insect development and is known to be involved in insect stress responses. In the current study, dopamine was analysed in
Aedes aegypti ...heads by HPLC. We found that immediately after adult emergence, males have significantly higher concentrations of dopamine than females, and that dopamine concentrations decrease with age in both sexes. Dopamine levels increase in females following a blood meal suggesting that dopamine might be involved in ovarian- and/or egg-development. We also found that female mosquitoes have a higher tolerance to a short term thermal stress in a water bath than males up to 44
°C, however, both sexes die if exposed to short term temperatures between 44 and 45
°C. Finally, we did not find any indication that dopamine levels were associated with short time thermal stress response in female mosquitoes.
Highlights • A. galli infection influenced vaccine-induced immunity to Newcastle Disease (ND) in chickens. • Parasitized NDV vaccinated chickens showed lower titres of NDV specific IgG and lower ...frequencies NDV-specific T cells in peripheral blood than non-parasitized vaccinated controls. • Upon NDV challenge, viral genomes persisted in the oral cavity for a slightly longer period of time in A. galli -infected NDV vaccinees as compared to non-parasitized NDV vaccines indicating an impact of A-galli on vaccine-induced protective immunity.
•Systemic immune gene expression in the spleen of Ascaridia galli infected chickens was assessed by microfluidic qPCR and found to vary at different time points after experimental infection.•At 2 ...weeks p.i., lL-13 expression was highly increased in infected chickens as compared to controls.•At 6 weeks p.i., increased expression of pro-inflammatory cytokine genes was observed in infected chickens.•A. galli specific IgG was detectable in serum of all infected chickens by 6 weeks p.i.•A. galli eggs in faeces were detectable in 43% of the infected chickens at week 6 p.i. and in 73% at week 9 p.i.
Ascaridia galli is a gastrointestinal nematode infecting chickens. Chickens kept in alternative rearing systems or at free-range experience increased risk for infection with resulting high prevalences. A. galli infection causes reduced weight gain, decreased egg production and in severe cases increased mortality. More importantly, the parasitised chickens are more susceptible to secondary infections and their ability to develop vaccine-induced protective immunity against other diseases may be compromised. Detailed information about the immune response to the natural infection may be exploited to enable future vaccine development. In the present study, expression of immune genes in the chicken spleen during an experimental infection with A. galli was investigated using the Fluidigm® BioMark™ microfluidic qPCR platform which combines automatic high-throughput with attractive low sample and reagent consumption. Spleenic transcription of immunological genes was compared between infected chickens and non-infected controls at week 2, 6, and 9 p.i. corresponding to different stages of parasite development/maturation. At week 2 p.i. increased expression of IL-13 was observed in infected chickens. Increased expression of MBL, CRP, IFN-α, IL-1β, IL-8, IL-12β and IL-18 followed at week 6 p.i. and at both week 6 and 9 p.i. expression of DEFβ1 was highly increased in infected chickens. In summary, apart from also earlier reported increased expression of the Th2 signature cytokine IL-13 we observed only few differentially expressed genes at week 2 p.i. which corresponds to the larvae histotrophic phase. In contrast, we observed increased expression of pro-inflammatory cytokines and acute phase proteins in infected chickens, by week 6 p.i. where the larvae re-enter the intestinal lumen. Increased expression of DEFβ1 was observed in infected chickens at week 6 p.i. but also at week 9 p.i. which corresponds to a matured stage where adult worms are present in the intestinal lumen.
Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth ...infections influence chicken health negatively, which is why the following investigation has been performed.
In the present experiment, 20 chickens of two inbred chicken lines containing the major histocompatibility complex (MHC) haplotypes, B14 and R5, were inoculated with 500 embryonated Ascaridia galli eggs. The A. galli-specific IgG titres of serum samples and the excretion of A. galli eggs in chicken faeces were measured for a period of 81 weeks.
The level of excreted A. galli eggs measured as eggs per gram chicken faeces (EPG) varied greatly between chickens in each line. Significant differences were found between the two lines and with the R5 chickens reaching the highest levels. Likewise, the A. galli-specific IgG titres in serum differed significantly between the two lines, and an inverse relationship between infection level (EPG) and antibody titres was found. Although this inverse relationship suggests that humoral immunity may be involved in protection against A. galli infection, the high antibody titres did not prevent continued infection.
Potent vaccine efficiency is crucial for disease control in both human and livestock vaccination programmes. Free range chickens and chickens with access to outdoor areas have a high risk of ...infection with parasites includingAscaridia galli, a gastrointestinal nematode with a potential influence on the immunological response to vaccination against other infectious diseases. The purpose of this study was to investigate whetherA. galliinfection influences vaccine-induced immunity to Newcastle Disease (ND) in chickens from an MHC-characterized inbred line. Chickens were experimentally infected withA. galliat 4 weeks of age or left as non-parasitized controls. At 10 and 13 weeks of age half of the chickens were ND-vaccinated and at 16 weeks of age, all chickens were challenged with a lentogenic strain of Newcastle disease virus (NDV).A. galliinfection influenced both humoral and cell-mediated immune responses after ND vaccination. Thus, significantly lower NDV serum titres were found in theA. galli-infected group as compared to the non-parasitized group early after vaccination. In addition, theA. galli-infected chickens showed significantly lower frequencies of NDV-specific T cells in peripheral blood three weeks after the first ND vaccination as compared to non-parasitized chickens. Finally,A. gallisignificantly increased local mRNA expression of IL-4 and IL-13 and significantly decreased TGF-ß4 expression in the jejunum two weeks after infection withA. galli. At the time of vaccination (six and nine weeks afterA. galliinfection) the local expression in the jejunum of both IFN-? and IL-10 was significantly decreased inA. galli-infected chickens. Upon challenge with the NDV LaSota strain, viral genomes persisted in the oral cavity for a slightly longer period of time inA. galli-infected vaccinees as compared to non-parasitized vaccinees. However, more work is needed in order to determine if vaccine-induced protective immunity is impaired inA. galli-infected chickens.
In chickens, the nematode Ascaridia galli is found with prevalences of up to 100% causing economic losses to farmers. No avian nematode vaccines have yet been developed and detailed knowledge about ...the chicken immune response towards A. galli is therefore of great importance. The objective of this study was to evaluate the induction of protective immune responses to A. galli soluble antigen by different immunization routes. Chickens were immunized with a crude extract of A. galli via an oral or intra-muscular route using cholera toxin B subunit as adjuvant and subsequently challenged with A. galli. Only chickens immunized via the intra-muscular route developed a specific A. galli antibody response. Frequencies of γδ T cells in spleen were higher 7 days after the first immunization in both groups but only significantly so in the intra-muscularly immunized group. In addition, systemic immunization had an effect on both Th1 and Th2 cytokines in caecal tonsils and Meckel's diverticulum. Thus both humoral and cellular immune responses are inducible by soluble A. galli antigen, but in this study no protection against the parasite was achieved.
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