Genetically engineered bacterial strains for the display of foreign peptides on filamentous phage

摘要

The present invention provides compositions and methods for increasing the efficiency of phage display. A first aspect of the present invention is a bacterial strain that stably comprises at least one gene that encodes a protein having a packaging function for a filamentous phage. A bacterial strain of the present invention can be transformed with a phage display expression construct that comprises a coat protein fusion protein or coat protein chimeric protein and used to generate packaged recombinant phage particles in the absence of a helper phage. In some preferred aspects of the invention, the bacterial strain contains ten of the eleven genes of an Ff filamentous phage that encode packaging functions, where a filamentous phage gene not contained by the bacterial strain is a coat protein gene that is provided on a phage display expression construct for the generation of fusion coat proteins or chimeric coat proteins. The present invention also includes methods of using a bacterial strain of the present invention to generate recombinant filamentous phage without the use of a helper phage. Preferred methods of the present invention include those that select for heavy chain and light chain antibody molecules with affinity for substances of interest. The invention also includes peptides and proteins identified using the methods of the present invention. Preferred peptides and proteins of the present invention include immunoglobulin heavy and light chains, and fragments thereof. Peptides or proteins selected for and identified using the methods of the present invention can be used for a variety of purposes, including research applications and therapeutic or diagnostic applications.