Immune status assessment by abundance of IFN-alpha and IFN-gamma mRNA in chicken blood

Studies on immunopathological changes induced by commercial IBD live vaccines in poultry birds

Intermediate plus live strain infectious bursal disease virus (IBDV) vaccines are used to control IBDV endemic infections in India. In the present study, immunopathological changes induced by commercial infectious bursal disease live vaccines with different immunization regimes were compared. A total of days old 108 Cobb broiler chicks were randomly divided into five groups with 24 chicks each in groups I, II, III and 18 chicks each in group IV and V. Group I served as control I (no immunization) and group II and III chicks were immunized with a single dose of vaccines 1 and 2 on 17th day of age (DOA), respectively. The group IV and V chicks were immunized with vaccines 1 and 2, respectively with primary dose on 17th DOA followed by booster dose on 24th DOA. Both intermediate plus live vaccines produced gross and histopathological lesions in lymphoid organs (bursa of Fabricius, thymus, spleen and caecal tonsils). Increased CD4 + , CD8 + T cells in affected bursa of Fabricius was evidenced by immunohistochemistry. Further, up-regulation in relative mRNA expression of IFN-γ, IL-1β and IL-6 were observed in bursa of Fabricius of treated birds, with maximum alteration particularly on 14th day post single immunization and 7th day post booster immunization. The findings suggest that single immunization regime on the 17th day of age showed immunization equivalent to booster immunization with lesser lesions, therefore, may be practiced and promoted in the field conditions for the better economic returns and animal welfare.

Bioactive polysaccharides and their potential health benefits in reducing the risks of atherosclerosis: A review

Atherosclerosis is a kind of lipid-driven chronic inflammatory disease of arteries and is the principal pathological basis of life-threatening cardiovascular disease events, such as strokes and heart attacks. Clinically, statins are the most commonly prescribed drugs for the treatment of atherosclerosis, but prolonged use of these drugs exhibit many adverse reactions and have limited efficacy. Polysaccharides are important natural biomacromolecules widely existing in plants, animals, microorganisms and algae. They have drawn considerable attention worldwide due to their multiple healthy functions, along with their non-toxic property. Importantly, a growing number of studies have demonstrated that bioactive polysaccharides exhibit prominent efficiency in controlling atherosclerotic risk factors like hyperlipemia, hypertension, oxidative stress, and inflammation. In recent decades, various bioactive polysaccharides with different structural features and anti-atherosclerotic potential from natural sources have been isolated, purified, and characterized. The aim of this review is to focus on the research progress of natural polysaccharides in reducing the risks of atherosclerosis based on evidence of in vitro and in vivo studies from 1966 to 2022. PRACTICAL APPLICATIONS: In the future, it is still necessary to strengthen the research on the development and mechanism of polysaccharides with anti-atherosclerotic potential. These anti-atherosclerotic polysaccharides with different structural characteristics and physiochemical properties from different sources will constitute a huge source of materials for future applications, especially in functional foods and drugs. The information summarized here may serve as useful reference materials for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents.

Analysis of porcine OSBPL5 gene allelic expression in skeletal muscle and association of a single-nucleotide polymorphism in the coding region with production traits

Genes that exhibit allelic expression imbalance and imprinted genes play important roles in the survival of the embryo and postnatal growth regulation. In this study, the porcine oxysterol-binding protein-related 5 (OSBPL5) gene was examined, and the 2140G>A mutation (rs318687202) was found in its coding region by a comparison of Laiwu and Landrace pigs. By allele-specific expression analysis based on a specific single-nucleotide polymorphism (SNP), the imprinting status of OSBPL5 gene in skeletal muscle from both neonate and adult pigs was determined. The results showed that the OSBPL5 was paternally imprinted in skeletal muscle from adults but biallelically expressed with predominantly maternal imprinting in neonates. The distribution of the 2140G>A SNP in four pig populations was analyzed, which showed that GG genotype was dominant in Duroc and Dapulian populations, whereas the AG genotype was dominant in Junmu-1 and Laiwu populations. Pigs with the GG genotype had significantly larger litters and greater cannon bone circumferences but a lower average daily gain than pigs with the AA genotype. In conclusion, we determined the difference in the allelic expression of OSBPL5 between adult and neonate pigs and identified an SNP in its coding region that is associated with production traits.

Characterization, functional and signaling elucidation of pigeon (Columba livia) interferon-α: Knockdown p53 negatively modulates antiviral response

The regulation of interferon-α signaling pathways is essential to protect the host from infection with a broad range of viruses. However, information regarding antiviral response and the specific molecular mechanism of Columba livia interferon-α (CoIFN-α) has not been reported to date. In this study, we cloned a 723bp complete ORF of CoIFN-α gene. The specific antiviral activity of CoIFN-α in VSV (TCID₅₀ = 10^-5.87/100 μL)-infected CEFs reached 5.5 × 10⁵ U/mg. Moreover, our result indicated that the anti-VSV efficient of CoIFN-α might depend on the expression of NF-κB. CoIFN-α also showed high sensitivity to trypsin and relatively stable after acid, alkali or heat treatment. Moreover, CoIFN-α activated STAT/Jak signaling and autophagy to inhibit VSV-induced apoptosis. Although the expression of p53 was further increased, apoptosis was not involved in CoIFN-α against VSV. Notably, although STAT signaling was efficiently activated, knockdown p53 did inhibit the antiviral activity of the CoIFN-α via decreasing the expression of Mx1 but not weakened Jak phosphorylation. Moreover, VSV aggravated the apoptosis and the expression of cleaved Mdm2 in knockdown p53 under preincubated CoIFN-α. Taken together, p53 might as a highly interconnected regulator in IFN-α antiviral response and cleaved Mdm2 might as a dominant-negative regulator by competing with full length Mdm2 for p53 binding in virus infection. Overall, our research not only enriches CoIFN-α antiviral features but also helps explain that p53 enhance the CoIFN-α antiviral response against pigeon viral diseases.

A bacterial ghost improves the immunological efficacy of a Newcastle disease virus inactivated vaccine

Newcastle disease (ND) is one of the most common contagious viral infectious diseases of poultry. Vaccination is an effective way to protect chickens from Newcastle disease virus (NDV), and large efforts have been made to acquire not only new vaccines but also new adjuvants to improve the efficiency of existing inactivated vaccines. Here, we observed the adjuvanticity of the bacterial ghost (BG) on the effectiveness of inactivated NDV vaccine in a chicken model. We found that BG, as an adjuvant with inactivated NDV vaccine, substantially strengthened the ND-specific antibody response and protection against lethal challenge in a chicken model, reduced viral shedding, strengthened the time duration of antibody titers, produced an available immunization effect with a low dose of vaccine, and improved serum IL-2 and IFN-γ concentrations. Our results demonstrate that BG significantly improved the immunogenicity of an inactivated NDV vaccine and is a new immune adjuvant candidate.

An infected chicken kidney cell co-culture ELISpot for enhanced detection of T cell responses to avian influenza and vaccination

A better understanding of the immune responses of chickens to the influenza virus is essential for the development of new strategies of vaccination and control. We have developed a method incorporating infected chicken kidney cells (CKC) in culture with splenocytes in an IFNγ ELISpot assay to enumerate ex vivo responses against influenza virus antigens. Splenocytes from birds challenged with influenza showed specific responses to the influenza virus, with responding cells being mainly CD8 positive. The utility of the assay was also demonstrated in the detection of an antigen specific enhancement of IFNγ producing cells from birds vaccinated with recombinant Fowlpox vectored influenza nucleoprotein and matrix protein.

•

Chickens infected with avian influenza developed IFNγ responses.

•

The use of infected CKC in ELISpot overcomes limitations at detection of responses.

•

This methods allows the quantification of influenza specific CD8 T cells.

•

The use of recombinant virus to infect CKC can further define antigen specificity.

Insight into alternative approaches for control of avian influenza in poultry, with emphasis on highly pathogenic H5N1

Highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 causes a devastating disease in poultry but when it accidentally infects humans it can cause death. Therefore, decrease the incidence of H5N1 in humans needs to focus on prevention and control of poultry infections. Conventional control strategies in poultry based on surveillance, stamping out, movement restriction and enforcement of biosecurity measures did not prevent the virus spreading, particularly in developing countries. Several challenges limit efficiency of the vaccines to prevent outbreaks of HPAIV H5N1 in endemic countries. Alternative and complementary approaches to reduce the current burden of H5N1 epidemics in poultry should be encouraged. The use of antiviral chemotherapy and natural compounds, avian-cytokines, RNA interference, genetic breeding and/or development of transgenic poultry warrant further evaluation as integrated intervention strategies for control of HPAIV H5N1 in poultry.

Abundance of IFN-α and IFN-γ gene transcripts and absence of IL-2 transcripts in the blood of chickens vaccinated with live or inactivated NDV

As immune responses to live and inactivated vaccines might differ, temporal responses of broiler chickens to vaccination were examined on the basis of the abundance in the circulating blood of gene transcripts of IFN-α, IFN-γ and IL-2, critical cytokines for immune responses. Blood samples were collected 6, 12 and 24 hours, and 7 and 14 days following vaccination with either live or inactivated Newcastle disease virus, La Sota strain, at 14 days of age, and the abundance of transcripts for each cytokine was assayed by real-time RT-PCR. Physiological saline and vaccine emulsion without viral antigen were administered to control groups for live and inactivated vaccine groups, respectively. The abundance of IFN-γ transcripts was elevated during the early times following vaccination and had reached baseline by the seventh day but the abundance of IFN-α transcripts remained elevated. Transcripts for neither IFN gene were detected in the control birds. The abundance of transcripts for each IFN was not different between the two vaccinated groups at any time. Transcripts for IL-2 were detected only in spleens from chicken embryos that had been inoculated with the live virus. The results show that cells stimulated to produce IFN-α and IFN-γ enter the circulating blood but those stimulated to produce IL-2 do not, or in very low number, and the IFN responses to both vaccines are the same.

An Assay in Microtitre Plates for Absolute Abundance of Chicken Interferon Alpha Transcripts

Immunosuppression of commercial chickens is a serious animal health and economic problem in the poultry industry. The major causes of the immunosuppression are viruses that suppress transcription of interferon genes, especially interferon alpha. There is a need for monitoring immunosuppression in commercially bred chickens. For this purpose, the absolute abundance of interferon alpha transcripts can be measured in blood of chickens by a suitable assay. Such an assay was used to estimate abundance of chicken interferon alpha in a sample of splenic cells induced with polyinosinic polycytidylic acid. The abundance measured was 29 ± 2 attomoles/µg total RNA. This assay can be performed in microtitre plates using samples collected from chickens in poultry houses.

Local and systemic immune responses following infection of broiler-type chickens with avian Metapneumovirus subtypes A and B

Infections with avian Metapneumovirus (aMPV) are often associated with swollen head syndrome in meat type chickens. Previous studies in turkeys have demonstrated that local humoral and cell-mediated immunity plays a role in aMPV-infection. Previous experimental and field observations indicated that the susceptibility of broilers and their immune reactions to aMPV may differ from turkeys. In the presented study local and systemic immune reactions of broilers were investigated after experimental infections with subtypes A and B aMPV of turkey origin. Both virus subtypes induced a mild respiratory disease. The recovery from respiratory signs correlated with the induction of local and systemic aMPV virus-neutralizing antibodies, which began to rise at 6 days post infection (dpi), when the peak of clinical signs was observed. In a different manner to the virus neutralizing (VN) and IgG-ELISA serum antibody titres, which showed high levels until the end of the experiments between 24 and 28 dpi, the specific IgA-ELISA and VN-antibody levels in tracheal washes decreased by 10 and 14 dpi, respectively, which may explain the recurring aMPV-infections in the field. Ex vivo cultured spleen cells from aMPV-infected broilers released at 3 and 6 dpi higher levels of IFN-γ after stimulation with Concanavalin A as compared to virus-free birds. In agreement with studies in turkeys, aMPV-infected broilers showed a clear CD4+ T cell accumulation in the Harderian gland (HG) at 6 dpi (P<0.05). In contrast to other investigations in turkeys aMPV-infected broilers showed an increase in the number of CD8alpha+ cells at 6 dpi compared to virus-free birds (P<0.05). The numbers of local B cells in the Harderian gland were not affected by the infection. Both aMPV A and B induced up-regulation of interferon (IFN)-γ mRNA-expression in the nasal turbinates, while in the Harderian gland only aMPV-A induced enhanced IFN-γ expression at 3 dpi. The differences in systemic and local T cell and possibly natural killer cell activity in the HG between turkeys and chickens may explain the differences in aMPV-pathogenesis between these two species.

Effects of supplemental chromium on interferon-gamma (IFN-gamma) mRNA expression in response to Newcastle disease vaccine in broiler chicken

We report the effects of supplemental chromium (Cr) on interferon-gamma (IFN-gamma) expression in response to Newcastle disease virus (NDV) vaccine in broiler chicken. Two hundred and eighty day old straight run broiler chicks were randomly selected and allocated at random to one of the seven treatment groups replicated four times having 10 chicks in each replication. Treatment 1 (C) was a standard control diet in which no Cr was offered to birds either through feed or drinking water. In treatments 2-4 (F500, F1000 and F1500), Cr in the form of chromium picolinate (CrPic) was added at rates of 500, 1000 and 1500 ppb in diets, respectively. In treatments 5-7 (W250, W500 and W750), Cr as added to the drinking water at rates of 250, 500 and 750 ppb, respectively. The feeding was continued from 1 to 49 d of age. On 49 d, three birds from each replicate, i.e. 12 birds/treatment were inoculated intramuscularly with R(2)B strain of NDV. Twelve unvaccinated birds along with 12 vaccinated birds from each treatment (four birds each day) were then sacrificed on 1, 3 and 7 days post-immunization to study the IFN-gamma expression using quantitative real time PCR. Following the immunization, the IFN-gamma mRNA expression in spleen was significantly (P<0.01) either up-regulated or down-regulated at day 1 and day 3 post-stimulation. Whereas, IFN-gamma mRNA expression reached basal level in all the vaccinated groups at day 7 post-stimulation. IFN-gamma mRNA expression on day 1 was approximately two and four times higher than the control (C) levels in F500 and W500 groups, respectively. On 3 day post-immunization, IFN-gamma mRNA expression in spleen was about 40 and 27 times higher than controls (C) in F500 and W500 groups, respectively. Other groups (F1000, F1500, W250 and W750) showed down-regulation of IFN-gamma mRNA expression. The results suggested that the dosage of chromium modulates the expression of IFN-gamma and route has effect on the onset and duration of the response. Thus, the supplementation of chromium at appropriate dose might be helpful to enhance the IFN-gamma mRNA expression in response to NDV.

The Interferon-α Genes from Three Chicken Lines and Its Effects on H9N2 Influenza Viruses

The interferon-alpha genes from three chicken lines were cloned by a direct PCR technique, and the effects of recombinant protein expressed in a prokaryotic system on highly pathogenic H9N2 influenza viruses were investigated. The cloned ChIFN-alpha gene encoded a protein of 193 amino acids with a signal sequence of 31 amino acids and mature peptides of 162 amino acids. Comparison of ChIFN-alpha sequences, detected six amino acids substitutions at positions 50, 58, 65, 81, 181, and 183. Homology analysis indicated that ChIFN-alpha genes could be subdivided into two lineages, SH-ChIFN-alpha and WJ-ChIFN-alpha. In addition, both SH-ChIFN-alpha and WJ-ChIFN-alpha were expressed with the N-terminal 6 consecutive histidine residues in a high-level prokaryotic expression system. Recombinant chicken interferon-alpha (rChIFN-alpha) protein has anti-VSV activity of more than 1 x 10(8) U/mg. Moreover, High concentration (10,000U) of rSH-ChIFN-alpha resulted in over 40% inhibition of the H9N2 virus infection in chicken embryos (Ovo), and 100% inhibition from one day-old to five day-old chickens (Vivo). The results suggested that rChIFN-alpha is a potential agent against many Chicken viral strains.

Chicken lines differ in production of interferon-like activity by peripheral white blood cells stimulated with phytohemagglutinin

Interferon (INF) activity was evaluated in the supernatants from peripheral white blood cells (WBC) of chickens from six lines. The WBC were cultured in flasks or 24-well plates with medium or medium and phytohemagglutinin (PHA). After 2 to 5 d, duplicate supernatant samples were tested for INF activity, i.e., the log2 titer inhibiting 50% destruction of the cytopathic effect of vesicular stomatitis virus on primary chick embryo fibroblasts. Also triplicate WBC samples were tested for proliferation by [H3]-thymidine labeling and scintillation counting. In the absence of PHA, INF was significant for only two lines, i.e., 7(2) (two trials) and C (one trial). With PHA the level of INF produced was similar if flasks were sampled daily or on successive days. The INF levels were highest using 10 or 20 microg/mL PHA, but line differences were best distinguished using 5 or 10 microg/mL. In three trials there was a low correlation between PHA-stimulated WBC proliferation and INF titer (r > or = 0.30; P < 0.05). It was concluded that supernatants from chicken WBC stimulated with 10 microg/mL PHA contain INF, and inbred Lines 72 and C repeatedly produce more INF than inbred Lines 63 and 15I(5). This is the first evidence for line differences in INF production in chickens, and these lines may be useful for characterization of the relevant genes and their importance in immune response(s) and disease resistance.

Chicken anemia virus and infectious bursal disease virus interfere with transcription of chicken IFN-alpha and IFN-gamma mRNA

Chicken anemia virus (CAV) and infectious bursal disease virus (IBDV) are the two most important viruses that cause immunosuppression in commercial chickens. Because inapparent, subclinical infections by these viruses cause immunosuppression, there is need for assessment of the immune status of chickens. Interference with induction of transcription for chicken interferon-alpha (ChIFN-alpha) and ChIFN-gamma was noted after subclinical infections with either CAV or IBDV. Because the immunosuppressive viruses of chickens may interfere with transcription for ChIFN-alpha and ChIFN-gamma, we propose using this interference to assess the immune status of chickens.

Cytokines of birds: conserved functions--a largely different look

Targeted disruptions of the mouse genes for cytokines, cytokine receptors, or components of cytokine signaling cascades convincingly revealed the important roles of these molecules in immunologic processes. Cytokines are used at present as drugs to fight chronic microbial infections and cancer in humans, and they are being evaluated as immune response modifiers to improve vaccines. Until recently, only a few avian cytokines have been characterized, and potential applications thus have remained limited to mammals. Classic approaches to identify cytokine genes in birds proved difficult because sequence conservation is generally low. As new technology and high throughput sequencing became available, this situation changed quickly. We review here recent work that led to the identification of genes for the avian homologs of interferon-alpha/beta (IFN-alpha/beta) and IFN-gamma, various interleukins (IL), and several chemokines. From the initial data on the biochemical properties of these molecules, a picture is emerging that shows that avian and mammalian cytokines may perform similar tasks, although their primary structures in most cases are remarkably different.