Enhancement of protective efficacy of innate immunostimulant based formulations against yolk sac infection in young chicks.

This study was conducted to characterize and compare the protective effects of various innate immune stimulants against yolk sac infection (YSI) caused by an avian pathogenic Escherichia coli in young chicks. The immune stimulants were administered alone or in various combinations of unmethylated CpG oligodeoxynucleotides (CpG), polyinosinic:polycytidylic acid (Poly I:C), and avian antimicrobial peptides (AMPs). Routes included in ovo or in ovo followed by a subcutaneous (S/C) injection.

Characterization of Dosage Levels for In Ovo Administration of Innate Immune Stimulants for Prevention of Yolk Sac Infection in Chicks.

Innate immune stimulants, especially toll-like receptor (TLR) ligands and agonists, are the main players in the initiation of innate immunity and have been widely studied as alternatives to antibiotics to control infection. In the present study, we characterized the dosage levels of various innate immune stimulants, including unmethylated cytosine-phosphate-guanosine dinucleotide -containing oligodeoxynucleotides (CpG ODN), polyinosinic-polycytidylic acid (poly I:C), cyclic polyphosphazene 75B (CPZ75B), avian beta-defensin 2 (ABD2), and combinations of these reagents given in ovo. Data derived from a series of animal experiments demonstrated that the in ovo administration of 10-50 µg CpG ODN/embryo (on embryonic day 18) is an effective formulation for control of yolk sac infection (YSI) due to avian pathogenic () in young chicks.

Avian antimicrobial peptides: in vitro and in ovo characterization and protection from early chick mortality caused by yolk sac infection.

Increasing antibiotic resistance is a matter of grave concern for consumers, public health authorities, farmers, and researchers. Antimicrobial peptides (AMPs) are emerging as novel and effective non-antibiotic tools to combat infectious diseases in poultry. In this study, we evaluated six avian AMPs including 2 truncated cathelicidins, [CATH-1(6-26) and CATH-2(1-15)], and 4 avian β-defensins (ABD1, 2, 6 and 9) for their bactericidal and immunomodulatory activities.

In Ovo Administration of Innate Immune Stimulants and Protection from Early Chick Mortalities due to Yolk Sac Infection.

Omphalitis or yolk sac infection (YSI) and colibacillosis are the most common infectious diseases that lead to high rates of early chick mortalities (ECMs) in young chicks. Out of numerous microbial causes, avian pathogenic Escherichia coli (APEC) or extraintestinal pathogenic E. coli infections are considered the most common cause of these conditions.

Immune responses to in ovo vaccine formulations containing inactivated fowl adenovirus 8b with poly[di(sodium carboxylatoethylphenoxy)]phosphazene (PCEP) and avian beta defensin as adjuvants in chickens.

Inclusion body hepatitis (IBH) is one of the major viral infections causing substantial economic loss to the global poultry industry. The disease is characterized by a sudden onset of mortality (2-30%) and high morbidity (60-70%). IBH is caused by a number of serotypes of fowl adenovirus with substantially low levels of serotype cross protection.

Administration of Poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) and Avian Beta Defensin as Adjuvants in Inactivated Inclusion Body Hepatitis Virus and its Hexon Protein-Based Experimental Vaccine Formulations in Chickens.

Inclusion body hepatitis (IBH) is one of the major infectious diseases adversely affecting the poultry industry of the United States and Canada. Currently, no effective and safe vaccine is available for the control of IBH virus (IBHV) infection in chickens. However, based on the excellent safety and immunogenic profiles of experimental veterinary vaccines developed with the use of new generation adjuvants, we hypothesized that characterization of vaccine formulations containing inactivated IBHV or its capsid protein hexon as antigens, along with poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) and avian beta defensin 2 (ABD2) as vaccine adjuvants, will be helpful in development of an effective and safe vaccine formulation for IBH.

CpG-ODNs induced changes in cytokine/chemokines genes expression associated with suppression of infectious bronchitis virus replication in chicken lungs.

The process of virus replication in host cells is greatly influenced by the set of cytokines, chemokines and antiviral substances activated as a result of host-virus interaction. Alteration of cytokines profiles through manipulation of the innate immune system by innate immune stimulants may be helpful in inhibiting virus replication in otherwise permissive cells. The aim of present studies was to characterize innate immune responses capable of inhibiting infectious bronchitis virus (IBV) replication in chicken lungs after in ovo administration of CpG ODN.

Pathotypic and molecular characterization of a fowl adenovirus associated with inclusion body hepatitis in Saskatchewan chickens.

Inclusion body hepatitis (IBH) is one of the major global disease problems, causing significant economic losses to poultry industry of the United States and Canada. The disease is characterized by its sudden onset and high mortalities. Amongst different serotypes of fowl adenoviruses (FAdVs) associated with IBH, serotype 8 of group I FAdV has been isolated from majority of IBH cases.

Administration of poly[di(sodium carboxylatoethylphenoxy)]phosphazene (PCEP) as adjuvant activated mixed Th1/Th2 immune responses in pigs.

The selection of an optimal adjuvant to enhance the potency and longevity of antigen specific immune responses has always been imperative for the development of more effective and safer vaccines. A balanced type of immune enhancing ability of a new adjuvant known as polyphosphazene (PCEP) has been demonstrated in mice. In the present study we have compared the humoral and cellular immune responses to vaccine formulations containing Actinobacillus pleuropneumoniae outer membrane antigen (OmlA) with PCEP or Emulsigen as adjuvants.

All three classes of CpG ODNs up-regulate IP-10 gene in pigs.

The analysis of CpG ODN induced innate immune responses in different animal species has shown substantial similarities and differences in levels and types of induced cytokines profile. The objectives of these studies were to identify innate immune biomarkers activated by three classes of CpG ODNs in pigs. For this purpose, we investigated the kinetics of innate immune responses in immune cells from pigs following in vitro and in vivo stimulation with CpG ODNs.

CpG oligodeoxynucleotides activate innate immune response that suppresses infectious bronchitis virus replication in chicken embryos.

The understanding of innate immune modulation by pathogens and immune-modulating agents, including synthetic oligodeoxynucleotides (CpG ODNs), has offered several new approaches to improve prophylactic and therapeutic strategies against infectious diseases in humans and animals. However, in this regard not much work has been done in avian medicine. In the present study, we analyzed the kinetics of interferon (IFN), cytokine, and chemokine mRNA expression in chicken embryonic spleen at 6 hr, 24 hr, 48 hr, and 72 hr after administration of CpG ODN 2007 (B-class) in 18-day-old chicken embryos.

Oligodeoxynucleotides containing CpG motifs (CpG-ODN) predominantly induce Th1-type immune response in neonatal chicks.

Earlier, we demonstrated that intramuscular administration of oligodeoxynucleotides containing CpG motifs (CpG-ODN) induces protection in neonatal chicks against a lethal challenge of Escherichia coli. However, the mechanism of induction of the protection was not clear. In an attempt to elucidate the mechanism of induced protection, we determined the kinetics of expression of cytokines/chemokines in the spleen and bursa of Fabricius of newly hatched chicks that had received intramuscular administration of CpG-ODN or non-CpG ODN compared to saline-treated controls.

Attenuated cytokine responses in porcine lymph node cells stimulated with CpG DNA are associated with low frequency of IFNalpha-producing cells and TLR9 mRNA expression.

The immune stimulatory effects of synthetic CpG DNA, on porcine peripheral blood mononuclear cells (PBMC) have been reported, but little is known about CpG-induced responses in other lymphoid tissues of pigs. We investigated innate immune responses induced by CpG DNA in cells from blood, lymph nodes (LN) and spleens of pigs. Porcine PBMC and lymph node cells (LNC) were stimulated in vitro with three classes (A-, B- and C-class) of CpG oligodeoxynucleotides (ODNs), and a non-CpG control ODN.

Systemic innate immune responses following intrapulmonary delivery of CpG oligodeoxynucleotides in sheep.

Mucosal delivery of CpG oligodeoxynucleotide (ODN) in mice has been shown to induce potent innate immunostimulatory responses and protection against infection. We evaluated the efficacy of CpG ODN in stimulating systemic innate immune responses in sheep following delivery to the pulmonary mucosa. Intrapulmonary (IPM) administration of B-Class CpG ODN in saline induced transient systemic responses which included increased rectal temperatures, elevated serum 2'5'-A synthetase and haptoglobin concentrations.

Innate immune responses induced by classes of CpG oligodeoxynucleotides in ovine lymph node and blood mononuclear cells.

CpG ODN signal through Toll-like receptor 9 (TLR9) and trigger a cascade of events that lead to activation of innate and adaptive immune responses. Our current understanding of the immunobiology of host responses to CpG is based largely on studies on peripheral blood mononuclear cells (PBMC) and splenocytes. Little is known regarding CpG-induced responses in other lymphoid tissues.

Immune mechanisms and therapeutic potential of CpG oligodeoxynucleotides.

Unmethylated CpG motifs in bacterial DNA and synthetic oligodeoxynucleotides activate immune cells that express Toll-like Receptor 9. Activation through this receptor triggers cellular signaling that leads to production of a proinflammatory and a Th1-type, antigen-specific immune response. The immunostimulatory effects of CpG oligodeoxynucleotides confer protection against infectious disease, allergy and cancer in animal models, and clinical trials have been initiated.

Transcriptional analysis of avian embryonic tissues following infection with avian infectious bronchitis virus.

Avian infectious bronchitis virus (IBV) infection is one of the major viral respiratory diseases of chickens. Better understanding of the molecular basis of viral pathogenesis should contribute significantly towards the development of improved prophylactic, therapeutic and diagnostic reagents to control infections. In the present investigation, transcriptional profiles were analyzed by using RNA recovered from the lung tissue of IBV infected 18-day-old chicken embryos at 6, 24, 48 and 72 h post IBV infection.

Sequence analysis of the matrix (M2) protein gene of avian pneumovirus recovered from turkey flocks in the United States.

We here report the comparative sequence and phylogenetic analysis of the avian pneumovirus subgroup C (APV C) matrix (M2) gene of cell culture-adapted isolates and clinical samples. Limited heterogeneity was observed among the M2 sequences, suggesting that diagnostic tests and vaccines against APV C are likely to exhibit broad cross-reactivity.

A single subtype of avian pneumovirus circulates among Minnesota turkey flocks.

The recent emergence of avian pneumovirus (APV) infection among US turkey flocks has resulted in a major economic threat to the turkey industry. In order to elucidate the molecular epidemiology of APV, comparative sequence analysis of the fusion (F) protein gene of APV was performed for 3 cell culture-adapted isolates and 10 APV positive clinical samples recovered from US turkey flocks. Relatively modest levels of nucleotide and amino acid sequence divergence were identified, suggesting the prevalence of a single lineage of APV among US turkey flocks.