Serum albumin nanoparticles vaccine provides protection against a lethal Pseudomonas aeruginosa challenge.

Pseudomonas aeruginosa is an opportunistic pathogen that causes severe infections in immunocompromised individuals and in patients with cystic fibrosis. A range of vaccines to prevent infections caused by P. aeruginosa has already been tested, yet no vaccine against this pathogen is currently available. The goal of this study was to evaluate the potential of bovine serum albumin nanoparticles (BSA-NPs) associated with total P. aeruginosa ATCC 27853 antigens in inducing protection against the infection with virulent P. aeruginosa PA14 strain in murine model of nasal infection. Swiss mice were immunized with BSA-NPs associated with total P. aeruginosa antigens (NPPa) or empty NPs (NPe). As positive and negative control, groups of animals were immunized with total antigens of P. aeruginosa ATCC 27853 and phosphate buffered saline, respectively. Immunized mice were infected via nasal route using P. aeruginosa PA14 strain. The survival after 48 h was evaluated and the lungs from animals were processed for quantification of bacterial load, cytokine expression and histopathological analysis. After infection with P. aeruginosa PA14, animals immunized with NPPa had the highest survival rate, the lowest bacterial lung load, a controlled production of cytokines and few histopathological changes. These results indicate that NPPa immunization protected mice from infection, contributing for the elimination of the bacteria from the lungs, which consequently reflected the survival of the animals. Therefore, this vaccine was able to induce a functional response in an animal model of lethal infection and thereby is a promising platform for P. aeruginosa vaccines.

Bovine serum albumin nanoparticles induce histopathological changes and inflammatory cell recruitment in the skin of treated mice.

Albumin is a natural, biocompatible, biodegradable and nontoxic polymer and due to these features, nanoparticles made of albumin are a good system for drug or antigen delivery. Polymeric nanoparticles are being widely explored as new vaccines platforms due to the capacity of those nanoparticles to prime the immune system by providing sustained release of the antigen after injection. Biodegradable nanoparticles associated with proteins represent a promising method for in vivo delivery of vaccines. In our previous studies, bovine serum albumin nanoparticles (BSA-NPs) were identified as a promising system for in vivo delivery of microbial antigens. The aim of this work was to show the effect of BSA-NPs on skin after nanoparticles administration. The pro-inflammatory activity of BSA-NPs was evaluated using in vivo models. BSA-NPs are easily uptake by macrophagic RAW 264.7 and BHK-21 cells without any significant cytotoxicity. Histological examination of skin sections from BSA-NPs-treated mice revealed intense cellular infiltration, increased skin thickness, follicular hypertrophy, vascular congestion and marked collagenesis. Mice immunized with recombinant non-structural protein 1 (rNS1) from Dengue virus 1 and BSA-NPs showed a high seroconversion rate if compared to animals immunized only with rNS1. Therefore, the effect of BSA-NPs on skin after BSA-NPs administration has a biotechnological relevance to the rational design of vaccine formulations based on albumin nanocarriers. However in the next years future studies should be carried out to best characterize the effect of BSA-NPs on dendritic cells and establish the role of these nanoparticles as a new vaccine platform for infectious diseases or cancer.