Specific-pathogen free (SPF) chickens were inoculated with the plasmid constructs encoding the fusion (F) and haemagglutinin-neuraminidase (HN) glycoproteins of Newcastle disease virus (NDV), either individually or in combination and challenged with velogenic NDV. The antibody level against NDV was measured using commercial enzyme linked immunosorbent assay (ELISA). In the first immunization regimen, SPF chickens inoculated twice with NDV-F or NDV-HN constructs elicited antibody responses 1 week after the second injection. However, the levels of the antibody were low and did not confer significant protection from the lethal challenge. In addition, administration of the plasmid constructs with Freund's adjuvant did not improve the level of protection. In the second immunization regimen, chickens inoculated twice with the plasmid constructs emulsified with Freund's adjuvant induced significant antibody titers after the third injection. Three out of nine (33.3%) chickens vaccinated with pEGFP-HN, five of ten (50.0%) chickens vaccinated with pEGFP-F and nine of ten (90.0%) chickens vaccinated with combined pEGFP-F and pEGFP-HN were protected from the challenge. No significant differences in the levels of protection were observed when the chickens were vaccinated with linearized pEGFP-F. The results suggested that more than two injections with both F and HN encoding plasmid DNA were required to induce higher level of antibodies for protection against velogenic NDV in chickens.
Vibrio anguillarum causes high mortality in European sea bass (Dicentrarchus labrax) larviculture. In this study, we evaluated if the recombinant sea bass ferritin-H could stimulate the innate immune system of gnotobiotic European sea bass larvae resulting in protection against a V. anguillarum challenge. We also evaluated the effect of a V. anguillarum infection on the transcription of immune-related genes in gnotobiotic European sea bass larvae. Recombinant sea bass ferritin-H was produced, encapsulated in calcium alginate microparticles and orally delivered to sea bass larvae at seven days after hatching. Our results showed V. anguillarum caused an acute infection, resulting in high mortality. The infection significantly upregulated the expression of tlr3, tlr5, cas1, il1β, tnfα, mif, il10, cc1, cxcl8 at 18, 24 and 36 h post infection, but not of the chemokine receptor genes cxcr4 and ccr9. There was no protective effect of ferritin-H. Remarkably, ferritin-H caused significantly higher transcript levels for cxcr4 and ccr9. Sea bass ferritin-H was more likely involved in immune-suppression and results point in the direction of a negative regulation of CXCR4 resulting in inhibition of cell proliferation, differentiation and migration which is detrimental to innate immunity and might explain the non-protective effect of ferritin-H in fish larvae.
Canine atopic dermatitis (AD) is a chronic, inflammatory and pruritic allergic skin disease in dogs. House dust mites such as Dermatophagoides farinae are one of the known causative agents for the induction of canine AD worldwide. D. farinae protein Der f 2 is known as an important allergen involved in canine AD and recently, Zen-1 has also been identified as an allergenic protein. There is limited information on the prevalence and role of allergen sensitization to crude D. farinae extract (CDF), Der f 2 and Zen-1 among dogs diagnosed with AD in Malaysia. The aim of this study was to determine the proportion of CDF-, Der f 2- and Zen-1-specific reactive sera among dogs diagnosed with AD in Malaysia using an enzyme-linked immunosorbent assay (ELISA). Serum samples were collected from dogs diagnosed with AD from several veterinary clinics in Malaysia. The canine case records were retrieved and information on signalment, dermatological and non-dermatological histories, clinical presentation, food allergies, and exclusion of ectoparasitic, microbial and fungal skin infections were obtained through a survey form. All serum samples were evaluated to quantify the CDF-, Der f 2- and Zen-1-specific immunoglobulin E (IgE) levels. A total of 24.6%, 48.4% and 29.8% of dogs diagnosed with AD were positive for CDF-, Der f 2- and Zen-1-specific IgE, respectively. These results suggest that CDF-, Der f 2- and Zen-1 are important allergens that can contribute to AD in dogs in Malaysia, and serological testing can be performed to provide additional treatment options involving specific immunotherapies.
Aujeszky's disease (AD) is a viral infectious disease caused by Suid herpesvirus 1 (SuHV-1). Vaccination and eradication of AD in domestic pigs is possible using marker vaccines with attenuated or inactivated SuHV-1, or subunit vaccines. However, vaccines with attenuated SuHV-1 have shown to be more potent in inducing strong cell-mediated immune response. The studies have shown that Parapoxvirus ovis, as well as Propionibacterium granulosum with lipopolysacharides (LPS) of Escherichia coli have pronounced immunomodulatory effects and that in combination with the vaccines can induce stronger humoral and cellular immune responses than use of vaccines alone. In our study distribution of peripheral blood T cell subpopulations was analysed after administration of vaccine alone (attenuated SuHV-1), immunostimulators (inactivated Parapoxvirus ovis or combination of an inactivated P. granulosum and detoxified LPS of E. coli) and combinations of vaccine with each immunostimulator to the 12-week old piglets. Throughout the study no significant changes were found in the proportions of γδ and most αβ T cell subpopulations analysed. However, on the seventh day of the study combination of an inactivated P. granulosum and LPS of E. coli with vaccine induced transient but significant increase of the proportions of CD4+CD8α+ and CD4-CD8α+ αβ T cells, that have been strongly associated with early protection of SuHV-1 infected pigs. Our findings indicate that combination of inactivated P. granulosum and detoxified E. coli LPS could be used for enhancement of a cellular immune response induced by vaccines against AD.