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

The release requirements for vaccine antigens 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 antigens are slowly released, resulting in prolonged antigen residence.