Expression of chicken interleukin-2 by a highly virulent strain of Newcastle disease virus leads to decreased systemic viral load but does not significantly affect mortality in chickens.

Background: In mammals, interleukin 2 (IL-2) has been shown to decrease replication or attenuate pathogenicity of numerous viral pathogens (herpes simplex virus, vaccinia virus, human respiratory syncytial virus, human immunodeficiency virus) by activating natural killer cells (NK), cytotoxic T lymphocytes and expanding subsets of memory cells. In chickens, IL-2 has been shown to activate T cells, and as such it might have the potential to affect replication and pathogenesis of Newcastle disease virus (NDV).

Methods: To assess the effect of IL-2 during NDV infection in chickens, we produced a recombinant virulent NDV strain expressing chicken IL-2 (rZJ1-IL2).

Incorporation of membrane-bound, mammalian-derived immunomodulatory proteins into influenza whole virus vaccines boosts immunogenicity and protection against lethal challenge.

Background: Influenza epidemics continue to cause morbidity and mortality within the human population despite widespread vaccination efforts. This, along with the ominous threat of an avian influenza pandemic (H5N1), demonstrates the need for a much improved, more sophisticated influenza vaccine. We have developed an in vitro model system for producing a membrane-bound Cytokine-bearing Influenza Vaccine (CYT-IVAC).

A novel method to incorporate bioactive cytokines as adjuvants on the surface of virus particles.

Cytokines have been used extensively as adjuvants in vaccines. However, practical considerations limit their use; diffusion from antigen, short half-lives and additional production costs. To address these problems we have developed a technology that efficiently produces inactivated, whole-virus influenza vaccine bearing membrane-bound cytokines.

A recombinant turkey herpesvirus expressing chicken interleukin-2 increases the protection provided by in ovo vaccination with infectious bursal disease and infectious bronchitis virus.

In ovo vaccination remains an attractive option for the mass application of vaccines to poultry, ensuring a uniform application of vaccine in a cost-effective manner. However, the number of vaccines that can be delivered safely by this method is limited. Several infectious bursal disease virus (IBDV) vaccines can be given in ovo though most are delivered post-hatch and there are no currently licensed embryo-safe infectious bronchitis virus (IBV) vaccines.

Expression of chicken interleukin-2 by turkey herpesvirus increases the immune response against Marek's disease virus but fails to increase protection against virulent challenge.

As Marek's disease virus continues to evolve towards greater virulence, more efficacious vaccines will be required in the future. We expressed chicken interleukin-2 (IL-2) from a turkey herpesvirus (HVT) in an attempt to increase the efficacy of HVT as a vaccine against Marek's disease. The recombinant IL-2/HVT was safe for in ovo vaccination, although it replicated less in the birds compared with the parent HVT strain.

In vivo analysis of the apoptosis-inducing effect of anti-endothelial cell antibodies in systemic sclerosis by the chorionallantoic membrane assay.

Objective: Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology characterized by mononuclear cell infiltration and fibrosis. Vascular injury occurs early in the course of disease, and previous in vitro studies suggest a primary role for anti-endothelial cell antibodies (AECAs) in mediating endothelial cell apoptosis. The aim of the present study was to analyze the apoptosis-inducing effect of AECAs in vivo.

Alternate forms of MHC class II-associated invariant chain are not produced by alternative splicing in rainbow trout (Oncorhynchus mykiss) but are encoded by separate genes.

A major limiting factor in understanding teleost major histocompatibility receptor function is the lack of knowledge about antigen presentation accessory molecules. We report here two cDNA clones encoding teleost versions of invariant chain and one encoding a related protein that may play a protease inhibition role in antigen presentation. The two invariant chain equivalents are similar to each other where they overlap, but differ in the presence or absence of a thyroglobulin domain.

Cloning of a novel rainbow trout (Oncorhynchus mykiss) CC chemokine with a fractalkine-like stalk and a TNF decoy receptor using cDNA fragments containing AU-rich elements.

An activation-specific cDNA library was made from phytohaemagglutinin (PHA)-activated haematopoietic cells of the rainbow trout (Oncorhynchus mykiss) using the technique of suppression subtractive hybridization. Several immune system genes were identified, including an interleukin (IL)1 receptor related protein and two invariant chain-like proteins. Many clones showed no similarity by BLAST search, but had AU-rich elements.

Mutational analysis of chicken interleukin 2.

Chicken interleukin 2 (chIL-2) has low, but significant, homology to both mammalian IL-2 and mammalian IL-15. In view of its unique phylogenetic position and potential use as a vaccine adjuvant, a detailed mutational analysis for critical functional sites was undertaken. It was found that Asp17 is a critical N terminal contact site for binding to the putative chIL-2 receptor, which is similar to results obtained for mammalian IL-2 and IL-15.

Production and in vitro characterization of recombinant chicken interleukin-2.

Mammalian interleukin-2 (IL-2) is a well-characterized cytokine that plays key roles in T cell differentiation and activation, B cell development, and natural killer (NK) cell stimulation. Chicken IL-2, which is the first nonmammalian IL-2 cloned, differs substantially from mammalian IL-2 molecules. We undertook to study the functions of chicken IL-2 by producing recombinant molecules in prokaryotic and eukaryotic expression systems, determining the in vitro properties of these molecules, and examining the kinetics of endogenous IL-2 production in vitro.

Thyroid injury, autoantigen availability, and the initiation of autoimmune thyroiditis.

Iodine depletion prevents disease and iodine repletion, which may cause thyroid cell injury by reactive oxygen intermediates, initiates disease in the Obese Strain chicken model of spontaneous autoimmune thyroiditis (AT). To examine the role of cell injury and autoantigen availability in AT induction we compared the immune responses that followed blunt trauma to the OS thyroid in the absence of iodine and the administration of normal dietary iodine in the absence of thyroid injury. Serum thyroglobulin concentrations were elevated following thyroid injury and the extensive thyroid infiltrates had high macrophage/CD4+, CD8+, B cell ratios consistent with an acute inflammatory response.

A cloned chicken lymphokine homologous to both mammalian IL-2 and IL-15.

IL-2, cloned in several mammalian species, plays a critical role in immune system function. Indirect evidence suggests that IL-2-like molecules also exist in lower vertebrates, although none has been cloned. In view of the commercial importance of poultry and the lack of any IL-2 sequence data in lower vertebrates, we undertook to clone a chicken IL-2-like molecule.

Distinct regions of thyroglobulin control the proliferation and suppression of thyroid-specific lymphocytes in obese strain chickens.

The effect of thyroglobulin (Tg)iodination on the proliferation and suppression of thyroid-specific lymphocytes was examined in vivo in the obese strain (OS) and Cornell strain chicken models of autoimmune thyroiditis. Spleen cells from OS chickens were able to transfer disease to Cornell strain recipients. The ability to transfer disease was markedly reduced if the donors were raised on an iodine-depleting regimen.

The obese strain chicken as a model for human Hashimoto's thyroiditis.

The OS and the related Cornell C strain are interesting animal models for the study of the etiology of autoimmune thyroiditis. They are especially valuable for studying the etiologic role of thyroid abnormalities and abnormalities in the processing of iodine. Limitations of the model are the scarcity of immunological reagents for chickens, the absence of avian cloned thyroid-specific genes, minimal amounts of microsomal antibody and some differences between OS chickens and Hashimoto's patients in the types of thyroid abnormalities observed.

Thyroid cell injury is an initial event in the induction of autoimmune thyroiditis by iodine in obese strain chickens.

The present study examines the role of thyroid cell injury in the initiation of autoimmune thyroiditis by iodine in Obese strain (OS) chickens, a strain genetically susceptible to spontaneous autoimmune thyroiditis. OS and normal strain chickens were placed on an iodine depletion regimen started in ovo. This regimen is known to prevent thyroiditis in OS chickens.

Characterization of stimulatory surface molecular expression on avian T cells.

We have characterized a monoclonal antibody (AT389), produced by immunization of mice with 4-day-old avian Concanavalin A blasts, which recognizes a 38-40 kDa homodimer present on the surface of all chicken T cells. AT389 increased the spontaneous and IL-2-driven proliferation of 3-day-old T-cell blasts. This antibody, in synergy with IL-2, increased cellular proliferation and cell survival of T-cell blasts over time.

Identification of a G protein coupled receptor induced in activated T cells.

Many genes are induced after T cell activation to make a cell competent for proliferation and ultimately, function. Many of these genes encode surface receptors for growth factors that signal a cell to proliferate. We have cloned a novel gene (clone 6H1) that codes for a member of the G protein-coupled receptor superfamily.

Marek's disease virus-transformed chicken T-cell lines respond to lymphokines.

Current assays for chicken interleukin-2 (IL-2) utilize mitogen-activated lymphocytes. However, very high inter-assay variability and sporadic high background proliferation limit their usefulness. In view of the above, several Marek's disease virus (MDV)-transformed T-cell lines (which grow well in a serum-supplemented medium) were tested for a response to chicken IL-2 when grown in serum-free media.

The role of iodine in thyroid autoimmunity: from chickens to humans: a review.

Evidence has been presented to support the idea that iodine plays an important role in autoimmune thyroiditis. Excessive amounts induce thyroiditis in genetically susceptible animal strains, while intrathyroidal depletion of iodine prevents disease in strains susceptible to severe thyroiditis. While the mechanisms by which iodine promotes thyroiditis is unknown, several hypotheses have been proposed.

Uptake and metabolism of iodine is crucial for the development of thyroiditis in obese strain chickens.

To assess the importance of the role of thyroidal iodine in the pathogenesis of thyroiditis in the obese strain (OS) chicken, a model of spontaneous and severe disease, we studied the effect of antithyroid drugs that reduce thyroidal iodine or prevent its metabolism. Reduction of thyroidal iodine was achieved with KClO4, an inhibitor of iodine transport and mononitrotyrosine (MNT), a drug that promotes loss of thyroidal iodine as iodotyrosines. A regimen consisting of KClO4 and MNT administration beginning in ovo and continuing after hatching reduced thyroidal infiltration to 2% of control values and decreased thyroglobulin antibody (TgAb) production for as long as 9 wk.

Thyroidal iodine metabolism in obese-strain chickens before immune-mediated damage.

Several studies have shown that iodine plays a role in spontaneous autoimmune thyroiditis in man and other animals. In addition, abnormalities of iodine metabolism have been found in patients with Hashimoto's thyroiditis and in chickens of the obese strain (OS), an animal model of spontaneous autoimmune thyroiditis. We have examined several parameters of iodine metabolism before immune damage in this model and in the related Cornell strain (CS), a strain which develops a late-onset mild thyroiditis, to discover a possible causal relationship between altered iodine metabolism and the initiation of autoimmunity.

Antioxidants delay the onset of thyroiditis in obese strain chickens.

Dietary iodine has been shown to be important in the induction of thyroiditis in susceptible chicken strains although the underlying mechanism remains unknown. Iodine may exert its effects through the formation of reactive oxidative radicals which would cause thyroidal injury and initiate infiltration. We have tested this hypothesis by examining the ability of butylated hydroxyanisole (BHA), ethoxyquin, and other antioxidants to prevent thyroiditis in Obese strain (OS) chickens, a strain that develops severe disease by 4 weeks of age.

Iodine in autoimmune thyroiditis.

The aim of this chapter was to present a theory or concept of autoimmune disease that, in a sense, deemphasized the importance of immunoregulatory defects but rather concentrated on defects and/or changes in a target organ that might stimulate immune responses. Defects in immune regulation were not discussed because there is little evidence that generalized defects in immunoregulation occur in patients with autoimmune thyroid disease (38). There is some evidence of decreased numbers of thyroid-antigen-specific T-suppressor cells in patients with autoimmune thyroid disease; however, this has been detected only after the appearance of frank disease (38).