Protection Conferred by Gallid Alphaherpesvirus 2 Vaccines Against Immunosuppression Induced by Very Virulent Plus (vv+) Marek's Disease Virus Strains in Commercial Meat Type Chickens.

Very virulent plus Marek's disease virus (vv+MDV) induces severe immunosuppression in commercial chickens. In this study, we evaluated how three Gallid alphaherpesvirus 2 (GaHV-2) vaccines (CVI-988, rMd5-BAC∆Meq, and CVI-LTR) protected against two negative outcomes of vv+MDV infection: (1) reduced viability and frequency of immune cells in the spleen and (2) decreased efficacy of the CEO (chicken embryo origin) vaccine against infectious laryngotracheitis challenge. At 25 days post-infection with vv+MDV 686, all vaccines are protected against the reduced viability of splenocytes.

Temporal Changes in Splenic Immune Cell Populations following Infection with a Very Virulent plus MDV in Commercial Meat-Type Chickens.

Marek's disease virus (MDV) can cause severe immunosuppression in chickens. Our previous study showed that infection with very virulent plus (vv+) MDV strains of one-day-old commercial meat-type chickens possessing maternal antibodies against MDV resulted in severe depletion of splenocytes at 28-30 days of age. In the present study, we have investigated the effect of vv+MDV strain 686 on splenic immunophenotypes at 6, 20, and 30 days post-infection (dpi).

Screening and selection of eubiotic compounds possessing immunomodulatory and anti-Clostridium perfringens properties.

Eubiotics are water and/or feed additives used in poultry to promote gut health and control enteric burden of pathogens, including Clostridium perfringens. While several eubiotic compounds (ECs) are being introduced commercially, it is essential to devise an in vitro model to screen these compounds to assess their immunomodulatory and antimicrobial properties prior to their testing in vivo. A chicken macrophage cell-line (MQ-NCSU) was used to develop an in vitro model to screen the immunological and anti-C.

Immunization of turkeys with Clostridium septicum alpha toxin-based recombinant subunit proteins can confer protection against experimental Clostridial dermatitis.

Clostridial dermatitis (CD), caused by Clostridium septicum, is an emerging disease of increasing economic importance in turkeys. Currently, there are no effective vaccines for CD control. Here, two non-toxic domains of C.

Characterization of immune responses and immunopathology in turkeys experimentally infected with clostridial dermatitis-producing strains of Clostridium septicum.

Clostridium septicum is one of the major causative agents of clostridial dermatitis (CD), an emerging disease of turkeys, characterized by sudden deaths and necrotic dermatitis. Despite its economic burden on the poultry industry, the immunopathological changes and pathogen-specific immune responses are poorly characterized. Here, we used three strains of C.

Evaluation of Adjuvant Effect of Cytosine-Guanosine-Oligodeoxynucleotide in Meat-Type Chickens Coadministered with Herpesvirus of Turkey Vaccine.

Herpesvirus of turkey (HVT) increases activation of T cells in 1-day-old chickens when administered . This study evaluated whether adding cytosine-guanosine oligodeoxynucleotides (CpG ODNs) to the HVT vaccine could enhance the adjuvant effect of HVT. We used a CpG ODN dose of 10 g per egg.

In ovo feeding of probiotic lactobacilli differentially alters expression of genes involved in the development and immunological maturation of bursa of Fabricius in pre-hatched chicks.

Compelling evidence indicates that immunological maturation of the gut-associated lymphoid tissues, including the bursa of Fabricius, is dependent upon antigenic stimulation post-hatch. In view of these data, the present study investigated the impact of exposing the immune system of chick embryos to antigenic stimuli, via in ovo delivery of poultry-specific lactobacilli, on the expression of genes associated with early bursal development and maturation. Broiler line embryonated eggs were inoculated with 10 and 10 colony-forming units (CFUs) of an individual or a mixture of Lactobacillus species, including L.

In Ovo Vaccination with Recombinant Herpes Virus of the Turkey-Laryngotracheitis Vaccine Adjuvanted with CpG-Oligonucleotide Provides Protection against a Viral Challenge in Broiler Chickens.

Infectious laryngotracheitis (ILT) is an economically important disease in chickens. We previously showed that an in ovo adjuvantation of recombinant herpesvirus of the turkey-Laryngotracheitis (rHVT-LT) vaccine with CpG-oligonucleotides (ODN) can boost vaccine-induced responses in one-day-old broiler chickens. Here, we evaluated the protective efficacy of in ovo administered rHVT-LT + CpG-ODN vaccination against a wild-type ILT virus (ILTV) challenge at 28 days of age and assessed splenic immune gene expression as well as cellular responses.

Corrigendum: Effects of inoculation of multi-strain lactobacilli on cytokine gene expression and antibody-mediated immune responses in chickens.

[This corrects the article DOI: 10.3389/fvets.2020.

Cellular Immune Responses in Lymphoid Tissues of Broiler Chickens Experimentally Infected with Necrotic Enteritis-Producing Strains.

Host cellular responses against (CP), the causative agent of necrotic enteritis (NE) in chickens, are poorly understood. In the present study, we first tested the NE-producing ability of seven CP strains (CP5, CP18, CP26, CP64, CP67, CP68, and NCNE-1), using an experimental infection model of broiler chickens. Evaluation of intestinal gross lesions showed that all the strains, except CP5, were able to produce NE, while CP26 and CP64 strains produced relatively more severe lesions when compared with other groups.

Immune Response Evaluation in Commercial Turkeys Affected with Clostridial Dermatitis.

Clostridial dermatitis (CD), caused by and , is an economically important emerging disease of turkeys characterized by sudden deaths and necrotic dermatitis. Immune responses in CD-affected commercial turkeys are poorly understood. In the present study, was isolated from CD-affected commercial turkeys during a recent outbreak, and the tissues (skin, muscle, and spleen) were collected and analyzed for immune gene expression, along with samples from clinically healthy birds.

Intracloacal Inoculation of Broiler Chickens with Strains: Evaluation of Necrotic Enteritis Disease Development and Lymphoid Immune Responses.

Necrotic enteritis (NE) is an economically important disease of chickens. We have recently shown that inflammatory responses in chickens inoculated orally with virulent were spatially regulated. Here, we used previously virulence-characterized strains, avirulent CP5 and virulent CP18 and CP26, to assess the severity of NE and immune responses in broiler chickens when inoculated intracloacally.

In ovo HVT vaccination enhances cellular responses at hatch and addition of poly I:C offers minimal adjuvant effects.

In ovo vaccination with herpesvirus of turkey (HVT) hastens immunocompetence in chickens and the recommended dose (RD) of 6080 plaque-forming-units (PFU) offers the most optimal effects. In previous studies conducted in egg-type chickens, in ovo vaccination with HVT enhanced lymphoproliferation, wing-web thickness with phytohemagglutinin-L (PHA-L), and increased spleen and lung interferon-gamma(IFN-γ) andToll-like receptor 3 (TLR3) transcripts. Here, we evaluated the cellular mechanisms by which HVT-RD can hasten immunocompetence in one-day-old meat-type chickens, and also determined if HVT adjuvantation with a TLR3 agonist, polyinosinic-polycytidylic acid (poly(I:C)), could enhance vaccine-induced responses and provide dose-sparing effects.

Effect of CpG-Oligonucleotide in Enhancing Recombinant Herpes Virus of Turkey-Laryngotracheitis Vaccine-Induced Immune Responses in One-Day-Old Broiler Chickens.

Infectious laryngotracheitis (ILT) is an economically important disease of chickens. While the recombinant vaccines can reduce clinical disease severity, the associated drawbacks are poor immunogenicity and delayed onset of immunity. Here, we used CpG-oligonucleotides (ODN) as an adjuvant in boosting recombinant herpesvirus of turkey-laryngotracheitis (rHVT-LT) vaccine-induced responses in one-day-old broiler chickens.

Mucosal and systemic lymphoid immune responses against strains with variable virulence in the production of necrotic enteritis in broiler chickens.

Necrotic enteritis (NE), caused by , is an economically important disease of chickens. Although NE pathogenesis is moderately well studied, the host immune responses against are poorly understood. The present study used an experimental NE model to characterize lymphoid immune responses in the caecal tonsils (CT), bursa of Fabricius, Harderian gland (HG) and spleen tissues of broiler chickens infected with four +  strains (CP1, CP5, CP18, and CP26), of which CP18 and CP26 strains also carried the gene.

AAV-monoclonal antibody expression protects mice from Ebola virus without impeding the endogenous antibody response to heterologous challenge.

Filoviruses cause severe hemorrhagic fever with case fatality rates as high as 90%. Filovirus-specific monoclonal antibodies (mAbs) confer protection in nonhuman primates as late as 5 days after challenge, and FDA-approved mAbs REGN-EB3 and mAb114 have demonstrated efficacy against Ebola virus (EBOV) infection in humans. Vectorized antibody expression mediated by adeno-associated virus (AAV) can generate protective and sustained concentrations of therapeutic mAbs in animal models for a variety of infectious diseases, including EBOV.

Probiotics as Alternatives to Antibiotics for the Prevention and Control of Necrotic Enteritis in Chickens.

Necrotic enteritis (NE) in poultry is an economically important disease caused by type A bacteria. A global trend on restricting the use of antibiotics as feed supplements in food animal production has caused a spike in the NE incidences in chickens, particularly in broiler populations. Amongst several non-antibiotic strategies for NE control tried so far, probiotics seem to offer promising avenues.

Characterization of vaccine-induced immune responses against coccidiosis in broiler chickens.

Coccidiosis, caused by Eimeria protozoan species, is an economically important enteric disease of poultry. Although commercial live vaccines are widely used for disease control, the vaccine-induced protective immune mechanisms are poorly characterized. The present study used a commercial broiler vaccine containing a mixture of E.

Effects of therapeutic levels of dietary antibiotics on the cecal microbiome composition of broiler chickens.

Dietary antibiotics, including antibiotic growth promoters (AGPs), have been commonly used to improve health and growth of poultry. The present study investigated the effects of therapeutic doses of dietary antibiotics, including bacitracin methylene disalicylate (BMD), penicillin G potassium (PP) and an ionophore (salinomycin, SA), on the cecal microbiome of chickens. BMD and SA treatments were given as dietary supplements from d 1 to 35 of age.

Differential Responsiveness to and by Avian Small Intestine Macrophages and T Cells.

Tissue resident immune system cells in the chicken intestine play a significant role in the protection against pathogens. However, very little is known about these cells. The current study was conducted to further characterize chicken intestinal immune system cells.

Necrotic enteritis in chickens: a review of pathogenesis, immune responses and prevention, focusing on probiotics and vaccination.

Necrotic enteritis (NE), caused by Clostridium perfringens (CP), is one of the most common of poultry diseases, causing huge economic losses to the poultry industry. This review provides an overview of the pathogenesis of NE in chickens and of the interaction of CP with the host immune system. The roles of management, nutrition, probiotics, and vaccination in reducing the incidence and severity of NE in poultry flocks are also discussed.

The Regulatory Microenvironment in Feathers of Chickens Infected with Very Virulent Marek's Disease Virus.

Vaccines against Marek's disease can protect chickens against clinical disease; however, infected chickens continue to propagate the Marek's disease virus (MDV) in feather follicles and can shed the virus into the environment. Therefore, the present study investigated if MDV could induce an immunoregulatory microenvironment in feathers of chickens and whether vaccines can overcome the immune evasive mechanisms of MDV. The results showed an abundance of CD4CD25 and CD4 transforming growth factor-beta (TGF-β) T regulatory cells in the feathers of MDV-infected chickens at 21 days post-infection.

Avian Macrophage Responses to Virulent and Avirulent .

The present study evaluated the avian macrophage responses against that varied in their ability to cause necrotic enteritis in chickens. Strains CP5 (avirulent-+), CP1 (virulent-+), and CP26 (highly virulent-++) were used to evaluate their effect on macrophages (MQ-NCSU cells) and primary splenic and cecal tonsil mononuclear cells. The bacilli (whole cells) or their secretory products from all three strains induced a significant increase in the macrophage transcription of Toll-like receptor (TLR)21, TLR2, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), and CD80 genes as well as their nitric oxide (NO) production and major histocompatibility complex (MHC)-II surface expression compared to an unstimulated control.

Effects of Treatment with Lactobacilli on Necrotic Enteritis in Broiler Chickens.

Growth promoter antibiotics have been commonly used for the control of necrotic enteritis (NE) in broilers for decades. However, due to a ban on the use of these antibiotics, alternatives such as probiotics have been tested widely for NE control. The present study tested the efficacy of four different species of lactobacilli (two isolates of Lactobacillus johnsonii and one of Ligilactobacillus (L.