Vaccine

The present invention relates to a genetically engineered protein comprising: at least one binding domain which is capable of binding to a cell surface protein on an avian antigen presenting cell; and a) at least one antigenic polypeptide orb) at least one binding domain which is capable of binding to at least one antigenic polypeptide. The present invention also relates to avian vaccines comprising at least one binding domain which is capable of binding to a cell surface protein on an avian antigen presenting cell; and a) at least one antigenic polypeptide or b) at least one binding domain which is capable of binding to at least one antigenic polypeptide and to the use of such vaccines to treat and/or prevent disease in avian subjects.