Oral and Parenteral Immunization of Chickens (Gallus gallus) Against West Nile Virus with Recombinant Envelope Protein

• Published in: Avian diseases 2009-12, Vol.53 (4), p.502-509
• Main Authors: Fassbinder-Orth, Carol A, Hofmeister, Erik K, Weeks-Levy, Carolyn, Karasov, William H
• Format: Article
• Language: English
• Subjects: adjuvants; Administration, Oral; Animals; Antibodies; Antibodies, Viral - blood; avian immunology; Birds; Chickens; coat proteins; Control groups; dosage; Dose-Response Relationship, Immunologic; drug delivery systems; ELISA; envelope protein; Enzyme linked immunosorbent assay; Gallus gallus; immune response; immunoglobulin A; immunoglobulin M; immunoglobulin Y; immunoglobulins; Infections; Injections, Intramuscular; intramuscular injection; Male; nonstructural protein; oral administration; oral vaccination; parenteral administration; Poultry Diseases - prevention & control; recombinant proteins; Recombinant Proteins - immunology; recombinant vaccines; Regular s; Therapeutic irrigation; Vaccination; viral antigens; viral diseases of animals and humans; Viral Envelope Proteins - immunology; Viral Vaccines - administration & dosage; Viral Vaccines - immunology; Viremia; Viremia - veterinary; Viruses; West Nile Fever - prevention & control; West Nile Fever - veterinary; West Nile virus
• ISSN: 0005-2086; 1938-4351
• DOI: 10.1637/8688-031009-Reg.1

West Nile virus (WNV) causes morbidity and mortality in humans, horses, and in more than 315 bird species in North America. Currently approved WNV vaccines are designed for parenteral administration and, as yet, no effective oral WNV vaccines have been developed. WNV envelope (E) protein is a highly antigenic protein that elicits the majority of virus-neutralizing antibodies during a WNV immune response. Leghorn chickens were given three vaccinations (each 2 wk apart) of E protein orally (20 µg or 100 µg/dose), of E protein intramuscularly (IM, 20 µg/dose), or of adjuvant only (control group) followed by a WNV challenge. Viremias were measured post-WNV infection, and three new enzyme-linked immunosorbent assays were developed for quantifying IgM, IgY, and IgA-mediated immune response of birds following WNV infection. WNV viremia levels were significantly lower in the IM group than in both oral groups and the control group. Total WNV E protein-specific IgY production was significantly greater, and WNV nonstructural 1-specific IgY was significantly less, in the IM group compared to all other treatment groups. The results of this study indicate that IM vaccination of chickens with E protein is protective against WNV infection and results in a significantly different antibody production profile as compared to both orally vaccinated and nonvaccinated birds.