ISCOM-like nanoparticles formulated with Quillaja brasiliensis Saponins are promising adjuvants for seasonal influenza vaccines

Vaccination is the most effective public health intervention to prevent influenza infections, which are responsible for an important burden of respiratory illnesses and deaths each year. Currently, licensed influenza vaccines are mostly split inactivated, although in order to achieve higher efficacy rates, some influenza vaccines contain adjuvants. Although split-inactivated vaccines induce mostly humoral responses, tailoring mucosal and cellular immune responses is crucial for preventing influenza infections. Quillaja brasiliensis saponin-based adjuvants, including ISCOM-like nanoparticles formulated with the QB-90 saponin fraction (IQB90), have been studied in preclinical models for more than a decade and have been demonstrated to induce strong humoral and cellular immune responses towards several viral antigens. Herein, we demonstrate that a split-inactivated IQB90 adjuvanted influenza vaccine triggered a protective immune response, stronger than that induced by a commercial unadjuvanted vaccine, when applied either by the subcutaneous or the intranasal route. Moreover, we reveal that this novel adjuvant confers up to a ten-fold dose-sparing effect, which could be crucial for pandemic preparedness. Last but not least, we assessed the role of caspase-1/11 in the generation of the immune response triggered by the IQB90 adjuvanted influenza vaccine in a mouse model and found that the cellular-mediated immune response triggered by the IQB90-Flu relies, at least in part, on a mechanism involving the casp-1/11 pathway but not the humoral response elicited by this formulation

Zika virus envelope domain III recombinant protein delivered with saponin-based nanoadjuvant from Quillaja brasiliensis enhances anti-zika immune responses, including neutralizing antibodies and splenocyte proliferation

Nanoadjuvants that combine immunostimulatory properties and delivery systems reportedly bestow major improvements on the efficacy of recombinant, protein-based vaccines. Among these, self-assembled micellar formulations named ISCOMs (immune stimulating complexes) show a great ability to trigger powerful immunological responses against infectious pathogens. Here, a nanoadjuvant preparation, based on saponins from Quillaja brasiliensis, was evaluated together with an experimental Zika virus (ZIKV) vaccine (IQB80-zEDIII) and compared to an equivalent vaccine with alum as the standard adjuvant. The preparations were administered to mice in two doses (on days zero and 14) and immune responses were evaluated on day 28 post-priming. Serum levels of anti-Zika virus IgG, IgG1, IgG2b, IgG2c, IgG3 were significantly increased by the nanoadjuvant vaccine, compared to the mice that received the alum-adjuvanted vaccine or the unadjuvanted vaccine. In addition, a robust production of neutralizing antibodies and in vitro splenocyte proliferative responses were observed in mice immunized with IQB80-zEDIII nanoformulated vaccine. Therefore, the IQB80-zEDIII recombinant preparation seems to be a suitable candidate vaccine for ZIKV. Overall, this study identified saponin-based delivery systems as an adequate adjuvant for recombinant ZIKV vaccines and has important implications for recombinant protein-based vaccine formulations against other flaviviruses and possibly enveloped viruses

Alternative inactivated poliovirus vaccines adjuvanted with quillaja brasiliensis or quil-a saponins are equally effective in inducing specific immune responses

Inactivated polio vaccines (IPV) have an important role at the final stages of poliomyelitis eradication programs, reducing the risks associated with the use of attenuated polio vaccine (OPV). An affordable option to enhance vaccine immunogenicity and reduce costs of IPV may be the use of an effective and renewable adjuvant. In the present study, the adjuvant activity of aqueous extract (AE) and saponin fraction QB-90 from Quillaja brasiliensis using poliovirus antigen as model were analyzed and compared to a preparation adjuvanted with Quil-A, a well-known saponin-based commercial adjuvant. Experimental vaccines were prepared with viral antigen plus saline (control), Quil-A (50 mg), AE (400 mg) or QB-90 (50 mg). Sera from inoculated mice were collected at days 0, 28, 42 and 56 post-inoculation of the first dose of vaccine. Serum levels of specific IgG, IgG1 and IgG2a were significantly enhanced by AE, QB-90 and Quil-A compared to control group on day 56. The magnitude of enhancement was statistically equivalent for QB-90 and Quil-A. The cellular response was evaluated through DTH and analysis of IFN-c and IL-2 mRNA levels using in vitro reestimulated splenocytes. Results indicated that AE and QB-90 were capable of stimulating the generation of Th1 cells against the administered antigen to the same extent as Quil-A. Mucosal immune response was enhanced by the vaccine adjuvanted with QB-90 as demonstrated by increases of specific IgA titers in bile, feces and vaginal washings, yielding comparable or higher titers than Quil-A. The results obtained indicate that saponins from Q. brasiliensis are potent adjuvants of specific cellular and humoral immune responses and represent a viable option to Quil-A

Genomic characterization of novel circular ssDNA viruses from insectivorous bats in southern Brazil

Circoviruses are highly prevalent porcine and avian pathogens. In recent years, novel circular ssDNA genomes have recently been detected in a variety of fecal and environmental samples using deep sequencing approaches. In this study the identification of genomes of novel circoviruses and cycloviruses in feces of insectivorous bats is reported. Pan-reactive primers were used targeting the conserved rep region of circoviruses and cycloviruses to screen DNA bat fecal samples. Using this approach, partial rep sequences were detected which formed five phylogenetic groups distributed among the Circovirusand the recently proposed Cyclovirus genera of the Circoviridae. Further analysis using inverse PCR and Sanger sequencing led to the characterization of four new putative members of the family Circoviridae with genome size ranging from 1,608 to 1,790 nt, two inversely arranged ORFs, and canonical nonamer sequences atop a stem loop

Quillaja brasiliensis saponin-based nanoparticulate adjuvants are capable of triggering early immune responses

Commercially available saponins are extracted from Quillaja saponaria barks, being Quil A® the most widely used. Nanoparticulate immunostimulating complexes (ISCOMs or ISCOMATRIX) formulated with these, are able to stimulate strong humoral and cellular immune responses. Recently, we formulated novel ISCOMs replacing QuilA® by QB-90 (IQB-90), a Quillaja brasiliensis leaf-extracted saponin fraction, and reported that IQB-90 improved antigen uptake, and induced systemic and mucosal antibody production, and T-cell responses. However, its mechanism of action remains unclear. In this study we provide a deeper insight into the immune stimulatory properties of QB-90 and ISCOMATRIX-like based on this fraction (IMXQB-90). We show herein that, when used as a viral vaccine adjuvant, QB-90 promotes an “immunocompetent environment”. In addition, QB-90 and IMXQB-90 induce immune-cells recruitment at draining-lymph nodes and spleen. Subsequently, we prove that QB-90 or IMXQB-90 stimulated dendritic cells secret IL-1β by mechanisms involving Caspase-1/11 and MyD88 pathways, implying canonical inflammasome activation. Finally, both formulations induce a change in the expression of cytokines and chemokines coding genes, many of which are up-regulated. Findings reported here provide important insights into the molecular and cellular mechanisms underlying the adjuvant activity of Q. brasiliensis leaf-saponins and its respective nanoparticles

Genomics and phenotypical characterization of two new lytic bacteriophages for biocontrol of Salmonella enterica

Aims: To perform the isolation, characterization and sequencing of the bacteriophages. To demonstrate that the bacteriophages can be used for biocontrol of different Salmonella enterica serovars. Study Design: This study was an experimental study. Place and Duration of Study: Bacteriology and Mycology Laboratory in the Veterinary Hospital at the Faculty of Agronomy and Veterinary Medicine of the University of Passo Fundo (FAMV/UPF), Biotechnology Center (CBiotec) of the Federal University of Paraíba (UFPB), Center for Microscopy and Microanalysis at the Faculty of Veterinary of the Federal University of Rio Grande do Sul (UFRGS), between January – September 2016. Methodology: Twelve Salmonella enterica serovars (S. Anatum, S. Agona, S. Brandenburg, S. Bredeney, S. Infantis, S. Lexington, S. Panama, S. Rissen, S. Schwarzengrund, S. Tennessee, S. Enteritidis ATCC 13076 and S. Typhimurium ATCC 14028) were selected to be the hosts. We isolate, purify, produce and determine the bacteriophage titers to verify the potential for lysis of these phages against the hosts. Having determined the action of the phages against the hosts, we performed the sequencing of the bacteriophages on the Illumina Mi-Seq platform and the morphology was performed by transmission electron microscopy (TEM). Results: We isolated, characterized and sequenced the genome of two new bacteriophages, Salmonella phage UPF_BP1, belonging to the family Podoviridae and Salmonella phage UPF_BP2, family Myoviridae. UPF_BP1 has lytic action against seven tested Salmonella enterica serovars, while UPF_BP2 has action against the twelve tested serovars. Conclusion: The two new bacteriophages have a lytic action against different Salmonella enterica serovars, feeding our expectations for the development of alternatives for the use of antimicrobials, being possible candidates for use as a biocontrol of Salmonella enterica in food, animals and the environment

Quillaja brasiliensis saponin-based nanoparticulate adjuvants are capable of triggering early immune responses

Commercially available saponins are extracted from Quillaja saponaria barks, being Quil A® the most widely used. Nanoparticulate immunostimulating complexes (ISCOMs or ISCOMATRIX) formulated with these, are able to stimulate strong humoral and cellular immune responses. Recently, we formulated novel ISCOMs replacing QuilA® by QB-90 (IQB-90), a Quillaja brasiliensis leaf-extracted saponin fraction, and reported that IQB-90 improved antigen uptake, and induced systemic and mucosal antibody production, and T-cell responses. However, its mechanism of action remains unclear. In this study we provide a deeper insight into the immune stimulatory properties of QB-90 and ISCOMATRIX-like based on this fraction (IMXQB-90). We show herein that, when used as a viral vaccine adjuvant, QB-90 promotes an “immunocompetent environment”. In addition, QB-90 and IMXQB-90 induce immune-cells recruitment at draining-lymph nodes and spleen. Subsequently, we prove that QB-90 or IMXQB-90 stimulated dendritic cells secret IL-1β by mechanisms involving Caspase-1/11 and MyD88 pathways, implying canonical inflammasome activation. Finally, both formulations induce a change in the expression of cytokines and chemokines coding genes, many of which are up-regulated. Findings reported here provide important insights into the molecular and cellular mechanisms underlying the adjuvant activity of Q. brasiliensis leaf-saponins and its respective nanoparticles

In-Depth Genomic Characterization of a Meropenem-nonsusceptible Pseudomonas otitidis Strain Contaminating Chicken Carcass

Background: The indiscriminate use of antibiotics in food-animal production has a major impact on public health, particularly in terms of contributing to the emergence and dissemination of antimicrobial resistant bacteria in the food-animal production chain. Although Pseudomonas species are recognized as important spoilage organisms in foodstuff, they are also known as opportunistic pathogens associated with hospital-acquired infections. Furthermore, Pseudomonas can play a role as potential reservoirs of antimicrobial resistance genes, which may be horizontally transferred to other bacteria. Considering that cephalosporins (3rd and higher generations) and carbapenems are critically important beta-lactam antimicrobials in human medicine, this study reports the occurrence and genomic characterization of a meropenem-nonsusceptible Pseudomonas otitidis strain recovered from a chicken carcass in Brazil.Materials, Methods & Results: During the years 2018-2019, 72 frozen chicken carcasses were purchased on the retail market from different regions in Brazil. Aliquots from individual carcass rinses were screened for Extended Spectrum Beta-lactamase (ESBL)-producing bacteria in MacConkey agar supplemented with 1mg.L-1 cefotaxime. Phenotypically resistant isolates were further tested for resistance to other antimicrobials and confirmed as ESBL-producers by means of disk-diffusion method using Müller-Hinton agar. Only one meropenen-nonsusceptible isolate was detected and submitted to whole genome sequencing (WGS) in Illumina Miseq. The strain was identified as Pseudomonas otitidis by local alignment of the 16S rRNA sequence using BLASTn and confirmed by Average Nucleotide Identity (ANI) analysis using JspeciesWS database. Genes encoding for antimicrobial resistance were detected by means of Resfinder and Comprehensive Antibiotic Resistance Database (CARD) databases. The phenotypic non-susceptibility to meropenen was attributed to the gene blaPOM-1. A total of 192 different genes encoding for quorum sensing system, antiphagocytosis, iron uptake, efflux pump, endotoxin and toxin, adherence, and secretion systems were detected by means of Virulence Factor Database (VFDB). Pseudomonas otitidis-pan genome was built using Roary-rapid large-scale prokaryote pan genome analysis using the present strain (K_25) and other two P. otitidis genomes (PAM-1, DSM 17224) publicly available at the NCBI. The core genome analysis of the two human strains resulted in similar percentages.Discussion: Carbapenems are critically important drugs for human health and bacterial strains resistant to these antimicrobials pose a public health problem. The blaPOM-1 gene harbored by the Pseudomonas otitidis K_25 strain encodes a metallo-beta-lactamase (MBL) conferring resistance to carbapenems. Pseudomonas otitidis was the first confirmed pathogenic Pseudomonas species expressing MBL constitutively in the absence of inducible beta-lactamase genes. Furthermore, the several virulence genes associated with the capacity of the P. otitidis K_25 to colonize, evade the immune system and cause lesions in the human host confirm this strain as a potential opportunistic pathogen contaminating foodstuff. These reinforce the need to address antimicrobial resistance in a One Health perspective, in which resistant bacteria and resistance determinants circulate among environment, animals and humans

Complete genome sequences of two bovine alphaherpesvirus 5 subtype C strains from southeast Brazil

Bovine alphaherpesvirus 5 causes meningoencephalitis in cattle, belongs to the Herpesviridae family, and can be divided into subtypes a, b, and c. Limited information is available about subtype c. Here, we report the complete genome sequences of two strains, P160/96, and ISO97/45, isolated from cattle in southeast Brazil