Interactions between lactobacilli and chicken macrophages induce antiviral responses against avian influenza virus.

Macrophages are an important cell type of the innate immune system that upon activation, can exert antiviral functions and also can induce virus-specific adaptive immune responses. Macrophage interaction with certain probiotic bacteria such as lactobacilli can enhance antiviral functions of these cells. We have previously shown that administration of lactobacilli to chickens can effectively augment immune response to vaccine antigens.

CpG oligonucleotide-mediated co-stimulation of mouse invariant natural killer T cells negatively regulates their activation status.

Invariant natural killer T (iNKT) cells play important roles in antimicrobial defense and immune-regulation. We have previously shown that iNKT cells express certain toll-like receptors (TLR), and that TLR co-stimulation of iNKT cells in the presence of suboptimal concentrations of T cell receptor (TCR) agonists enhances cellular activation. In the present study, we investigated the regulatory effects of CpG oligonucleotides in mouse primary hepatic and splenic iNKT cells and in DN32.

Cytokine Gene Expression in Lung Mononuclear Cells of Chickens Vaccinated with Herpesvirus of Turkeys and Infected with Marek's Disease Virus.

Marek's disease virus (MDV) enters the chicken host through the respiratory system. However, little is known about the host immune responses induced by MDV in the lungs. To characterize these responses, chickens were vaccinated with herpesvirus of turkeys (HVT) and challenged with the RB1B strain of MDV via the respiratory route.

Reduction of avian influenza virus shedding by administration of Toll-like receptor ligands to chickens.

Avian influenza viruses (AIV) are of concern to the poultry industry. Outbreaks of AIV highlight the urgent need for effective control measures. Prophylactic strategies should be explored that rapidly elicit immunity against the virus.

Induction of antiviral responses against avian influenza virus in embryonated chicken eggs with toll-like receptor ligands.

Early responses against viruses, such as avian influenza virus (AIV), may be induced by Toll-like receptor (TLR) pathways. In the present study, an in ovo model was employed to study the antiviral activities of TLR ligands. It was hypothesized that administration of TLR ligands in ovo at the appropriate dose and time can reduce AIV titer in embryonated chicken eggs.

Characterization of the effects of three Lactobacillus species on the function of chicken macrophages.

Lactobacillus acidophilus, Lactobacillus reuteri and Lactobacillus salivarius can influence the adaptive immune responses in chickens but vary in their ability to do so. The present study attempted to identify how these three bacteria alter the innate immune system. A chicken macrophage cell line, MQ-NCSU, was co-cultured with the three live Lactobacillus species, alone or in combination, grown at different temperatures for various durations of time.

Expression profiles of antiviral response genes in chicken bursal cells stimulated with Toll-like receptor ligands.

Cells of the adaptive immune system express Toll-like receptors (TLRs) and are able to respond to TLR ligands. With this in mind, the goal of the current study was to determine the expression of antiviral response genes in the cells of the chicken bursa of Fabricius (BF) to stimulation with TLR ligands. We investigated initially the response of bursal B cells to CpG-ODN, lipopolysaccharide (LPS) and poly(I:C) treatment.

TLR ligands induce antiviral responses in chicken macrophages.

Chicken macrophages express several receptors for recognition of pathogens, including Toll-like receptors (TLRs). TLRs bind to pathogen-associated molecular patterns (PAMPs) derived from bacterial or viral pathogens leading to the activation of macrophages. Macrophages play a critical role in immunity against viruses, including influenza viruses.

Effects of ligands for Toll-like receptors 3, 4, and 21 as adjuvants on the immunogenicity of an avian influenza vaccine in chickens.

Avian influenza viruses (AIV) are of great concern to the worldwide community as well as the poultry industry. Although existing vaccines are successful in limiting the spread of the virus, these vaccines do not eliminate virus shedding into the environment. As a result, it is of great importance to enhance the efficacy of existing AIV vaccines.

Avian influenza virus vaccines containing Toll-like receptors 2 and 5 ligand adjuvants promote protective immune responses in chickens.

Vaccination remains a useful means for the control of avian influenza viruses (AIV) in chickens. Current vaccines can protect chickens from morbidity and mortality. However, they do not eliminate virus shedding into the environment.

Selected lactic acid-producing bacterial isolates with the capacity to reduce Salmonella translocation and virulence gene expression in chickens.

Background: Probiotics have been used to control Salmonella colonization/infection in chickens. Yet the mechanisms of probiotic effects are not fully understood. This study has characterized our previously-selected lactic acid-producing bacterial (LAB) isolates for controlling Salmonella infection in chickens, particularly the mechanism underlying the control.

Immunostimulatory properties of Toll-like receptor ligands in chickens.

Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors that have been identified in mammals and avian species. Ligands for TLRs are typically conserved structural motifs of microorganisms termed pathogen-associated molecular patterns (PAMPs). Several TLRs have been detected in many cell subsets, such as in macrophages, heterophils and B cells, where they mediate host-responses to pathogens by promoting cellular activation and the production of cytokines.

A toll-like receptor 3 ligand enhances protective effects of vaccination against Marek's disease virus and hinders tumor development in chickens.

Marek's disease (MD) is caused by Marek's disease virus (MDV). Various vaccines including herpesvirus of turkeys (HVT) have been used to control this disease. However, HVT is not able to completely protect against very virulent strains of MDV.

Oral treatment of chickens with lactobacilli influences elicitation of immune responses.

Commensal microbes in the intestine are in constant interaction with host cells and play a role in shaping the immune system. Lactobacillus acidophilus, Lactobacillus reuteri, and Lactobacillus salivarius are members of the chicken intestinal microbiota and have been shown to induce different cytokine profiles in mononuclear cells in vitro. The objective of the present study was to examine the effects of these bacteria individually or in combination on the induction of antibody- and cell-mediated immune responses in vivo.

Assessment of bioactivity of a recombinant chicken interferon-gamma expressed using a baculovirus expression system.

The full-length coding sequence of chicken interferon-γ (ChIFN-γ) was cloned into a baculovirus nonfusion vector, pFastBacDual, and expressed in Sf21 insect cells. Recombinant ChIFN-γ (rChIFN-γ) protein was found to be expressed both intracellularly as well as in the culture supernatants. The affinity-purified rChIFN-γ contained 14, 17, and 28 kDa proteins, possibly representing both glycosylated and nonglycosylated protein forms of ChIFN-γ.

Transcriptome and proteome profiling of host responses to Marek's disease virus in chickens.

Marek's disease (MD) is an immunosuppressive and proliferative disease of domestic chickens caused by a highly oncogenic cell-associated alpha-herpesvirus, named Marek's disease virus (MDV). Despite the availability of highly efficacious vaccines for control of MD and existence of lines of chickens which display differential genetic susceptibility or resistance to this disease, little is known about the underlying mechanisms of MDV-host interactions. The recent advent of global or targeted gene and protein expression profiling has paved the way towards gaining a better understanding of host responses to MDV.

Effects of lactobacilli on cytokine expression by chicken spleen and cecal tonsil cells.

Lactobacillus acidophilus, Lactobacillus reuteri, and Lactobacillus salivarius are all normal residents of the chicken gastrointestinal tract. Given the interest in using probiotic bacteria in chicken production and the important role of the microbiota in the development and regulation of the host immune system, the objective of the current study was to examine the differential effects of these bacteria on cytokine gene expression profiles of lymphoid tissue cells. Mononuclear cells isolated from cecal tonsils and spleens of chickens were cocultured with one of the three live bacteria, and gene expression was analyzed via real-time quantitative PCR.

Expression of antimicrobial peptides in cecal tonsils of chickens treated with probiotics and infected with Salmonella enterica serovar typhimurium.

Several strategies currently exist for control of Salmonella enterica serovar Typhimurium colonization in the chicken intestine, among which the use of probiotics is of note. Little is known about the underlying mechanisms of probiotic-mediated reduction of Salmonella colonization. In this study, we asked whether the effect of probiotics is mediated by antimicrobial peptides, including avian beta-defensins (also called gallinacins) and cathelicidins.

Expression of cytotoxicity-associated genes in Marek's disease virus-infected chickens.

Cytotoxic host responses to Marek's disease virus (MDV) have been attributed to both natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). However, the mechanisms of cell lysis initiated by these cytotoxic responses during MDV infection are not well defined. Therefore, the current study was aimed at elucidating the molecular mechanisms of host cytotoxic responses to MDV infection by investigating the expression of genes in the cell lysis pathway involving granzyme A.

Interactions between commensal bacteria and the gut-associated immune system of the chicken.

The chicken gut-associated lymphoid tissue is made up of a number of tissues and cells that are responsible for generating mucosal immune responses and maintaining intestinal homeostasis. The normal chicken microbiota also contributes to this via the ability to activate both innate defense mechanisms and adaptive immune responses. If left uncontrolled, immune activation in response to the normal microbiota would pose a risk of excessive inflammation and intestinal damage.

Gene expression profiling of chicken lymphoid cells after treatment with Lactobacillus acidophilus cellular components.

Lactobacillus acidophilus has been shown to exert immunostimulating activities in a number of species, including the chicken. To examine the molecular mechanisms of this phenomenon, we investigated spatial and temporal expression of immune system genes in chicken cecal tonsil and spleen mononuclear cells in response to structural constituents of L. acidophilus.

Molecular cloning and expression analysis of chicken MyD88 and TRIF genes.

Toll-like receptors (TLRs) trigger the innate immune system by responding to specific components of microorganisms. MyD88 and TRIF are Toll/interleukin (IL)-1 (TIR)-domain containing adapters, which play essential roles in TLR-mediated signalling via the MyD88-dependant and -independent pathways, respectively. Genes encoding several TLRs have been identified in the chicken genome, however, elements of their signalling pathways have not been well characterized.

Construction of a microarray specific to the chicken immune system: profiling gene expression in B cells after lipopolysaccharide stimulation.

The objective of this study was to profile gene expression in cells of the chicken immune system. A low-density immune-specific microarray was constructed that contained genes with known functions in the chicken immune system, in addition to chicken-expressed sequence tags (ESTs) homologous with mammalian immune system genes, which were systematically characterized by bioinformatic analyses. Genes and ESTs that met the annotation criteria were amplified and placed on a microarray.