Rotavirus VP6 protein mucosally delivered by cell wall-derived particles from Lactococcus lactis induces protection against infection in a murine model.

C. Facundo Temprana,Laura E. Esteban,Marcelo H. Argüelles,Nicolás M. Gutierrez,Alejandro A. Castello,Graciela Glikmann,Dalila Silvestre,Marcelo G. Mandile,Patricia A. Barril,Paulo Lee Ho

doi:10.1371/journal.pone.0203700

Abstract

Rotaviruses are the primary cause of acute gastroenteritis in children worldwide. Although the implementation of live attenuated vaccines has reduced the number of rotavirus-associated deaths, variance in their effectiveness has been reported in different countries. This fact, among other concerns, leads to continuous efforts for the development of new generation of vaccines against rotavirus.In this work, we describe the obtention of cell wall-derived particles from a recombinant Lactococcus lactis expressing a cell wall-anchored version of the rotavirus VP6 protein. After confirming by SDS-PAGE, Western blot, flow cytometry and electronic immunomicroscopy that these particles were carrying the VP6 protein, their immunogenic potential was evaluated in adult BALB/c mice. For that, mucosal immunizations (oral or intranasal), with or without the dmLT [(double mutant Escherichia coli heat labile toxin LT(R192G/L211A)] adjuvant were performed. The results showed that these cell wall-derived particles were able to generate anti-rotavirus IgG and IgA antibodies only when administered intranasally, whether the adjuvant was present or not. However, the presence of dmLT was necessary to confer protection against rotavirus infection, which was evidenced by a 79.5 percent viral shedding reduction.In summary, this work describes the production of cell wall-derived particles which were able to induce a protective immune response after intranasal immunization. Further studies are needed to characterize the immune response elicited by these particles as well as to determine their potential as an alternative to the use of live L. lactis for mucosal antigen delivery.

Highlights

Rotavirus (RV) has been described as the primary cause of acute gastroenteritis in children worldwide with an incidence that does not correlate to the socioeconomic characteristics of the population, the mortality rates do [1]
The generation of a recombinant L. lactis expressing RV VP6 under the control of the nisin-inducible PnisA promotor, and anchored on the bacterial cell wall, was described [37]. This bacteria and L. lactis NZ9000 were used to generate the CWDP
In recent years the potential of L. lactis as live vaccine vectors has begun to be perceived. They are of great importance from the public health point of view since they have a high margin of safety with low production costs and are very easy to administer [41]

Summary

Introduction

Rotavirus (RV) has been described as the primary cause of acute gastroenteritis in children worldwide with an incidence that does not correlate to the socioeconomic characteristics of the population, the mortality rates do [1]. Since 2006 licensed vaccines against RV have been implemented [2,3] These vaccines were introduced each year in different countries and global mortality rates in children below five years old were reduced from 528,000 in the year 2000 to 215,000 in 2013 [4]. The most used vaccines, whether Rotarix (GlaxoSmithKline Biologicals, Rixensart, Belgium) or RotaTeq (Merck & Co. Inc., West Point, PA, USA), consist of attenuated strains (human attenuated or human/bovine reassortant, respectively). Inc., West Point, PA, USA), consist of attenuated strains (human attenuated or human/bovine reassortant, respectively) They do not confer sterilizing immunity to the vaccinated subject but confer protection from severe diarrhea, preventing patient death mainly in those countries where adequate health care cannot be provided immediately [2,5]

Methods

Results

Conclusion