Abstract: Provided herein are modified phage surface polypeptides, phages with modified surface polypeptides, nucleic acids that encode the modified surface polypeptides, and related vectors and phages comprising the vectors. The provided phage surface polypeptides optionally comprise one or more modifications, including, for example, one or more modifications to enhance targeting to an antigen-presenting cell and one or more modifications that destabilize a viral capsid. Further provided herein are methods of making a lambda phage with a modified surface polypeptide and methods of making a lambda phage with a plurality of modified surface polypeptides. Also provided herein are antigen delivery systems comprising the modified phages of the invention and methods of promoting an antigenic response in a subject by administering to the subject the antigen delivery system of the invention, alone or in combination with other immunization modalities.