Dose and timing requirements for immunogenicity of viral poultry vaccine antigen: investigations of emulsion-based depot function

Theo Jansen (1) , Marij Hofmans (2) , Marc Theelen (3) , Frans Manders (3) , Virgil Schijns (4)

1 Vaccine Technology & Immunology
2 Service Laboratory
3 vaccine technology & Immunology
4 Vaccine Technology & Immunology

The release requirements for vaccine antigens (Ags) delivered by adjuvants with presumed depot function are poorly understood. Water-in-oil (W/O) emulsions are routinely used in many poultry vaccines. They strongly activate antibody production, and are regarded as a depot from which Ags are slowly released, resulting in prolonged antigen residence. However, from earlier studies we concluded that W/O adjuvant activity is partly based on the immunostimulatory activity of the oil phase. Here we assessed the dose and regimen requirements for viral antigen in immunization experiments in chickens. Three-to-four week-old White Leghorn chickens were repeatedly injected with inactivated antigen of infectious bursal disease virus (IBDV) during 48 days. Our aim was to compare the antibody responses in repeatedly injected animals, receiving fractioned doses of antigen, to the responses in animals receiving only one injection of the full dose of Ag formulated in either a W/O emulsion or in saline. We observed that repeated administration of small amounts of Ag results in a gradual increase of specific humoral immune responses during the immunization regimen. Immunization with a higher first dose evoked an early higher antibody response, which however, reached a similar plateau level at the end the regimen. When compared to lower first dose regimens a slow decline of serum antibody titer following two weeks after arrest of Ag injections indicated that repeated injection of small doses of Ag indeed mimic the efficacy of depot-forming adjuvants. All regimens of fractioned antigen in saline, however, proved less effective, when compared to a single dose vaccination of the cumulative amount of antigen formulated in a W/O emulsion. From our data we confirm that W/O emulsions are very effective vaccine vehicles for improving antigen-specific humoral responses in chickens, due to a combination of antigen residence-prolonging activity and direct immune stimulation.

Mots clés: Life Sciences

Theo Jansen, Marij Hofmans, Marc Theelen, Frans Manders, Virgil Schijns. Dose and timing requirements for immunogenicity of viral poultry vaccine antigen: investigations of emulsion-based depot function. Avian Pathology, 2008, 36 (05), pp.361-365. ⟨10.1080/03079450701567395⟩. ⟨hal-00540089⟩