The pComb3 Phagemid Family of Phage Display Vectors

Abstract

A phagemid is a plasmid that contains the origin of replication and packaging signal of a filamentous phage. Following bacterial transformation, a phagemid can be replicated and amplified as a plasmid, using a double-stranded DNA origin of replication, or it can be replicated as single-stranded DNA for packaging into filamentous phage particles. The use of phagemids enables phage display of large proteins, such as antibody fragments. Phagemid pComb3 was among the first phage display vectors used for the generation and selection of antibody libraries in the 50-kDa Fab format, a monovalent proxy of natural antibodies. Affording a robust and versatile tool for more than three decades, phage display vectors of the pComb3 phagemid family have been widely used for the discovery, affinity maturation, and humanization of antibodies in Fab, scFv, and single-domain formats from naive, immune, and synthetic antibody repertoires. In addition, they have been used for broadening phage display to the mining of nonimmunoglobulin repertoires. This review examines conceptual, functional, and molecular features of the first-generation phage display vector pComb3 and its successors, pComb3H, pComb3X, and pC3C.

Improving Pharmacokinetics of Peptides Using Phage Display

“…However, phagemids lack most of the genes necessary for virion assembly and release, and for this reason, a helper phage that carries these genes is required for the production of viral progeny. Furthermore, the compact size of phagemid vectors simplifies their genetic manipulation and makes it possible to insert large sequences, and they have, for this reason, become the vector of choice for the display of large proteins such as full-length antibodies and antibody fragments [ 58 ].…”

Structure, Biology, and Applications of Filamentous Bacteriophages

“…Similar mutations are engineered in the helper phages used in phage display, to boost the production of particles containing phagemid vectors Vieira and Messing 1987). The phagemid vectors containing an expression cassette for construction of the virion protein fusions were key for broadening the size and display modes used in phage display libraries in comparison to phage vectors (Barbas et al 1991(Barbas et al , 2001Marks et al 1991;Sblattero and Bradbury 2000; see also Overview: The pComb3 Phagemid Family of Phage Display Vectors [Rader 2023]).…”

“…A truncated pIII, containing only the carboxy-terminal domain, is sufficient for assembly into the virion, as long as a signal sequence is present. Phage display phagemid vectors encoding the carboxyterminal domain of pIII are used as a platform for display of antibody variable domains (see Overview: The pComb3 Phagemid Family of Phage Display Vectors [Rader 2023]). The sequence encoding the fusion counterpart is inserted between a signal sequence and the pIII C domain (Barbas et al 2001).…”