Multivalent pIX Phage Display System

Phage display screening plays a key role in the identification of a multitude of antibody specificities, but identifying optimal candidates still remains a challenge. Creative Biolabs provides high-quality service in phage display antibody library construction and screening. Our scientists developed a pIX combinatorial display system, combining with the use of an engineered helper phage. This approach provides a generic alternative route for obtaining good binders with higher thermostability and affinity. Creative Biolabs is pleased to introduce our pIX library construction and screening service to our global clients.

Phage display has largely replaced hybridoma technology for therapeutic monoclonal antibody development. As there is a growing need for improved targeted therapeutic intervention, phage display technology has been extensively modified and improved since its introduction three decades ago. By far, pIII is the dominating display capsid used in antibody display and selection. However, the use of pIII is associated with well-documented negative effects on selection performance, such as clone-dependent reduced phage infectivity and propagation, which cause repertoire bias. Thus, the limitations in pIII display technology motivate the search for further improvements. Several reports have explored pIX as an alternative antibody display scaffold. pIX and pIII are located at opposite tips on the virion, and the two proteins differ in their mechanisms of translocation to the E. coli inner membrane prior to phage assembly. pIX lacks a signal sequence. It does not undergo post-translational processing and appears to depend on YidC for periplasmic targeting. Therefore, signal sequences are added to facilitate antibody display, but later reports are conflicting with respect to how well such pIX display performs in comparison to display on pIII.

Overview of pIX display routes (Høydahl et al. 2016).
Fig.1 Overview of pIX display routes (Høydahl et al. 2016).

Creative Biolabs has developed a multivalent pIX display system with the high hit-rate of specific clones in diverse antibody library selection, avoiding the use of a signal sequence to the fusion protein. This approach uses an engineered helper phage known to improve antibody pIX display and retrieval. Multivalent pIX phage display screening is suitable for distinct and improved antibody properties.

Key advantages including but not limited to:

Creative Biolabs’ scientists have extensive experience in pIX phage display library construction and screening. Our scientists have demonstrated that this approach translates into substantially improved retrieval of desired specificities with favorable biophysical properties in de novo selection. We are confident in providing clients with the best service at the most competitive cost.

For more detailed information, please feel free to contact us or directly sent us an inquiry.


  1. Høydahl, L.S.; et al. Multivalent pIX phage display selects for distinct and improved antibody properties. Sci Rep. 2016, 6:39066.

All listed customized services & products are for research use only, not intended for pharmaceutical, diagnostic, therapeutic or any in vivo human use.

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