A potential nanobiotechnology platform based on infectious bursal disease subviral particles

Abstract

We describe a novel nanobiotechnology platform based on subviral particles derived from infectious bursal disease virus (IBD-SVPs). The major virus coat protein VP2 assembles into spherical, 23 nm SVPs when expressed as a heterologous protein in the yeast Pichia pastoris. We recovered up to 38 mg of IBD-SVPs at > 95% purity from 1 L of recombinant yeast culture. The purified particles were able to tolerate organic solvents up to 20% concentration (ethanol or dimethylsulfoxide), they resisted temperatures up to 65 °C and remained stable over a wide pH range (2.5–9.0). We achieved bioconjugation to the amine groups of lysine residues and to the carboxyl groups of aspartic and glutamic acid residues, allowing the functionalization of IBD-SVPs with biotin. The accessibility of surface amine groups was measured using Alexa Fluor 488 N-hydroxysuccinimide (NHS) ester, an amine-selective fluorescent dye, revealing that approximately 60 dye molecules were attached to the surface of each particle. IBD-SVPs can therefore be exploited as a robust and versatile nanoscaffold to display diverse functional ligands.

Protective Oral Vaccination against Infectious bursal disease virus Using the Major Viral Antigenic Protein VP2 Produced in Pichia pastoris

“…We also conclude that unencapsulated, purified IBD-SVPs are stable enough in the chicken digestive tract to resist degradation until they are taken by M cells, which allows them to induce the immunocompetent cells located beneath. This confirms our previous observation that IBD-SVPs tolerate acidic conditions (pH 2.0) in vitro without becoming denatured [30] .…”

“…Fractions representing the 152-ml peak were collected, mixed and concentrated using nanosep centrifugal device with a 300-kDa molecular weight cut off (MWCO). As we previously reported [30] , 38 mg of IBD-SVPs with >95% purity was extracted from the cells harvested from 1 l of culture using an acidic buffer, followed by ammonium sulfate precipitation and SEC.…”

“…We previously described the production of IBD-SVPs in P. pastoris [30]. Here we report the oral delivery of yeast-derived recombinant IBD-VP2 from the vv strain IR01 [31] to young chickens.…”

“…Oral vaccine delivery is simple and inexpensive, but orally-delivered subunit vaccines tend to have limited and short-lived immunogenicity that must be addressed by boost regimes and/or the co-administration of adjuvants. We previously described the production of IBD-SVPs in P. pastoris [30] . Here we report the oral delivery of yeast-derived recombinant IBD-VP2 from the vv strain IR01 [31] to young chickens.…”

Oral Immunization With Plant-Based Vaccine Induces a Protective Response Against Infectious Bursal Disease

“…This suggests that, although the antigen is not bioencapsulated by plant cell wall, since our formulation consists of extracted proteins, VP2 is able to resist degradation in the digestive tract of chicken until it is taken by M cells which allows it to reach immunocompetent cells in the gut-associated lymphoid tissue (Taghavian et al, 2013). This resistance in the GIT might be explained by the fact that, as recently demonstrated by us and other authors, VP2 is able to correctly self-assemble into IBD-SVP in plant cells (Gómez et al, 2020;Marusic et al, 2021) that are very stable under harsh conditions (Taghavian et al, 2012;Gómez et al, 2020).…”