Recombinant Filamentous Bacteriophages Encapsulated in Biodegradable Polymeric Microparticles for Stimulation of Innate and Adaptive Immune Responses.

Rezvan Jamaledin,Concetta Di Natale,Paolo Antonio Netti,Raffaele Vecchione,Rossella Sartorius,Piergiuseppe De Berardinis

doi:10.3390/microorganisms8050650

Abstract

Escherichia coli filamentous bacteriophages (M13, f1, or fd) have attracted tremendous attention from vaccinologists as a promising immunogenic carrier and vaccine delivery vehicle with vast possible applications in the development of vaccines. The use of fd bacteriophage as an antigen delivery system is based on a modification of bacteriophage display technology. In particular, it is designed to express multiple copies of exogenous peptides (or polypeptides) covalently linked to viral capsid proteins. This study for the first time proposes the use of microparticles (MPs) made of poly (lactic-co-glycolic acid) (PLGA) to encapsulate fd bacteriophage. Bacteriophage–PLGA MPs were synthesized by a water in oil in water (w1/o/w2) emulsion technique, and their morphological properties were analyzed by confocal and scanning electron microscopy (SEM). Moreover, phage integrity, encapsulation efficiency, and release were investigated. Using recombinant bacteriophages expressing the ovalbumin (OVA) antigenic determinant, we demonstrated the immunogenicity of the encapsulated bacteriophage after being released by MPs. Our results reveal that encapsulated bacteriophages are stable and retain their immunogenic properties. Bacteriophage-encapsulated PLGA microparticles may thus represent an important tool for the development of different bacteriophage-based vaccine platforms.

Highlights

IntroductionBacteriophages are a powerful platform with outstanding potential in the biomedical and chemical engineering field that have been exploited for diverse applications including theranostics [1], batteries [2,3], drug delivery [4], and vaccine development [5]
Using recombinant bacteriophages expressing the ovalbumin (OVA) antigenic determinant, we demonstrated the immunogenicity of the encapsulated bacteriophage after being released by MPs
Bacteriophages are a powerful platform with outstanding potential in the biomedical and chemical engineering field that have been exploited for diverse applications including theranostics [1], batteries [2,3], drug delivery [4], and vaccine development [5]

Summary

Introduction

Bacteriophages are a powerful platform with outstanding potential in the biomedical and chemical engineering field that have been exploited for diverse applications including theranostics [1], batteries [2,3], drug delivery [4], and vaccine development [5]. Filamentous bacteriophages are single-strand DNA virions belonging to the Inoviridae family, a sub-group of non-lytic, rod-like shaped Escherichia coli viruses with a repeated and ordered capsid structure, and that includes phages f1, fd, and M13 [6]. Fd filamentous bacteriophage is a bio nano-fiber with a modifiable surface that is a promising vehicle for antigen expression. Fd bacteriophage genome is intrinsically rich in deoxycytidylate-phosphate-deoxy guanylate (CpG) regions, which can be recognized by toll-like receptors (TLRs). After activation of TLRs, signaling induces the generation of inflammatory signal mediators such as cytokines, and can develop adaptive immune responses without needing any exogenous adjuvant [11,12,13,14]

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