Biodistribution of filamentous phage peptide libraries in mice

Abstract

In vivo phage display is a new approach to acquire peptide molecules that bind stably to a given target. Phage peptide display libraries have been selected in mice and humans and numerous vasculature-targeting peptides have been reported. However, in vivo phage display has not typically produced molecules that extravasate to target specific organ or tumor antigens. Phage selections in animals have been performed for very short times without optimization for biodistribution or clearance rates to a particular organ. It is hypothesized that peptides that home to a desired antigen/organ can be obtained from in vivo phage experiments by optimization of incubation times, phage extraction and propagation procedures. To accomplish this goal, one must first gain a better understanding of the in vivo biodistribution and rate of clearance of engineered phage peptide display libraries. While the fate of wild type phage in rodents has been reported, the in vivo biodistribution of the commonly used engineered fd-tet M13 phage peptide display libraries (such as in the fUSE5 vector system) have not been well established. Here we report the biodistribution and clearance properties of fd-tet fifteen amino acid random peptide display libraries in fUSE5 phage in three common mouse models employed for drug discovery - CF-1, nude, and SCID mice.

In Vivo Selection and Validation of Liver-Specific Ligands Using a New T7 Phage Peptide Display System

“…This suggests that linear C-terminal peptides as a group may be difficult to adapt as therapeutic ligands, particularly if present as multiple copies. Whether N-terminal peptides displayed on filamentous phage are subject to similar limitations remains to be determined (Zou et al 2004).…”

“…As noted already in the pioneer study by Pasqualini et al, a substantial portion of injected peptide library displayed on phage fd-tet is nonspecifically sequestered by liver, which strongly interferes with selection of liver-specific peptides (Pasqualini and Ruoslahti 1996). A detailed study of phage clearance has shown that the commonly used display library FUSE5, containing random peptides at the N-terminus of the phage fd-tet protein pIII, disappears from the bloodstream of mice or loses its infectivity within 30 min after injection (Zou et al 2004).…”

Phage display and molecular imaging: expanding fields of vision in living subjects

“…Furthermore, in vivo homing has also been applied to human subjects (Arap et al 2002;Krag et al 2006). To refine in vivo homing protocols, a thorough biodistribution study with immunodeficient mice was performed, and circulation time was found to be a critical variable, depending on the organ or tissue being targeted (Zou et al 2004). …”

Potential of phage-displayed peptide library technology to identify functional targeting peptides

“…This application of the technology is early in development and will be interesting to follow to fruition. It is important to note here that the biodistribution and clearance properties of phage-displayed peptide libraries is dependent on the target organ, strains of mice and types of phage [77] and that researchers may need to try varying in vivo screening parameters to achieve success.…”