scholarly journals Characterization of a Novel Inactivated Salmonella enterica Serovar Enteritidis Vaccine Candidate Generated Using a Modified cI857/λ PR/GeneEExpression System

2012 ◽  
Vol 80 (4) ◽  
pp. 1502-1509 ◽  
Author(s):  
Chetan V. Jawale ◽  
Atul A. Chaudhari ◽  
Byung Woo Jeon ◽  
Rahul M. Nandre ◽  
John Hwa Lee
Keyword(s):  
Salmonella Enterica ◽  
Vaccine Candidate ◽  
Expression System ◽  
Secretory Iga ◽  
Effective Vaccine ◽  
Control Group ◽  
Bacterial Cells ◽  
Lysis Gene ◽  
Lymphocyte Proliferation Response ◽  
Cell Envelopes

ABSTRACTA new strategy to develop an effective vaccine is essential to control food-borneSalmonella entericaserovar Enteritidis infections. Bacterial ghosts (BGs), which are nonliving, Gram-negative bacterial cell envelopes, are generated by expulsion of the cytoplasmic contents from bacterial cells through controlled expression using the modified cI857/λ PR/geneEexpression system. In the present study, the pJHL99 lysis plasmid carrying the mutated lambda pR37-cI857 repressor and PhiX174 lysis geneEwas constructed and transformed inS. Enteritidis to produce a BG. Temperature induction of the lysis gene cassette at 42°C revealed quantitative killing ofS. Enteritidis. TheS. Enteritidis ghost was characterized using scanning and transmission electron microscopy to visualize the transmembrane tunnel structure and loss of cytoplasmic materials, respectively. The efficacy of the BG as a vaccine candidate was evaluated in a chicken model using 60 10-day-old chickens, which were divided into four groups (n= 15), A, B, C, and D. Group A was designated as the nonimmunized control group, whereas the birds in groups B, C, and D were immunized via the intramuscular, subcutaneous, and oral routes, respectively. The chickens from all immunized groups showed significant increases in plasma IgG and intestinal secretory IgA levels. The lymphocyte proliferation response and CD3+CD4+and CD3+CD8+T cell subpopulations were also significantly increased in all immunized groups. The data indicate that both humoral and cell-mediated immune responses are robustly stimulated. Based on an examination of the protection efficacy measured by observations of gross lesions in the organs and bacterial recovery, the candidate vaccine can provide efficient protection against virulent challenge.

scholarly journals A Lactic Acid Bacteria (LAB)-Based Vaccine Candidate for Human Norovirus

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 213 ◽  
Author(s):  
Kelsey Craig ◽  
Xianjun Dai ◽  
Anzhong Li ◽  
Mijia Lu ◽  
Miaoge Xue ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Vaccine Candidate ◽  
The United States ◽  
Effective Vaccine ◽  
Control Group ◽  
Post Inoculation ◽  
Mesenteric Lymph Nodes ◽  
Efficient Cell Culture System ◽  
Gnotobiotic Piglets

Human noroviruses (HuNoVs) are responsible for more than 95% of the non-bacterial acute gastroenteritis epidemics in the world. The CDC estimates that every year 21 million individuals suffer from HuNoV-induced gastroenteritis in the United States. Currently, there is no FDA-approved vaccine for HuNoVs. Development of an effective vaccine has been hampered by the lack of an efficient cell culture system for HuNoVs and a suitable small animal model for pathogenesis study. In this study, we developed lactic acid bacteria (LAB) as a vector to deliver HuNoV antigen. A LAB strain (Lactococcus lactis) carrying VP1 gene of a HuNoV GII.4 virus (LAB-VP1) was constructed. It was found that HuNoV VP1 protein was highly expressed by LAB vector and was secreted into media supernatants. To test whether LAB-based HuNoV vaccine candidate is immunogenic, 4-day-old gnotobiotic piglets were orally inoculated with various doses of LAB-VP1. It was found that LABs were persistent in the small intestine of piglets and shed in pig feces for at least 25 days post inoculation. LAB DNA and VP1 were detected in mesenteric lymph nodes and spleen tissue in LAB-VP1 inoculated groups. HuNoV-specific IgG and IgA were detectable in serum and feces respectively at day 13 post-inoculation, and further increased at later time points. After being challenged with HuNoV GII.4 strain, a large amount of HuNoV antigens were observed in the duodenum, jejunum, and ileum sections of the intestine in the LAB control group. In contrast, significantly less, or no, HuNoV antigens were detected in the LAB-VP1 immunized groups. Collectively, these results demonstrate that a LAB-based HuNoV vaccine induces protective immunity in gnotobiotic piglets.

scholarly journals Generation of a Novel Staphylococcus aureus Ghost Vaccine and Examination of Its Immunogenicity against Virulent Challenge in Rats

2015 ◽  
Vol 83 (7) ◽  
pp. 2957-2965 ◽  
Author(s):  
Nagarajan Vinod ◽  
Sung Oh ◽  
Hyun Jung Park ◽  
Jung Mo Koo ◽  
Chang Won Choi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Responses ◽  
Vaccine Candidate ◽  
Protective Efficacy ◽  
Control Group ◽  
Igg Antibody ◽  
Content Type ◽  
Wide Range ◽  
Virulent Challenge ◽  
Cell Envelopes

Staphylococcus aureusis a Gram-positive pathogen that causes a wide range of infections in humans and animals. Bacterial ghosts are nonliving, empty cell envelopes and are well represented as novel vaccine candidates. In this study, we examined the immunogenicity and protective efficacy ofS. aureusghosts (SAGs) against a virulent challenge in rats. Nonliving SAGs were generated by using the MIC of sodium hydroxide. The formation of a transmembrane lysis tunnel structure in SAGs was visualized by scanning electron microscopy. To investigate these SAGs as a vaccine candidate, rats were divided into four groups, A (nonimmunized control), B (orally immunized), C (subcutaneously immunized), and D (intravenously immunized). The IgG antibody responses were significantly stronger in the SAG-immunized groups than in the nonimmunized control group (P< 0.05). Moreover, a significant increase in the populations of CD4+and CD8+T cells was observed in all three immunized groups (P< 0.05). We also found that serum bactericidal antibodies were significantly elicited in the SAG-immunized groups (P< 0.05). Most importantly, the bacterial loads in the immunized groups were significantly lower than those in the nonimmunized control group (P< 0.01). These results suggest that immunization with SAGs induces immune responses and provides protection against a virulentS. aureuschallenge.

scholarly journals A Highly Effective Component Vaccine against Nontyphoidal Salmonella enterica Infections

mBio ◽  
2015 ◽  
Vol 6 (5) ◽  
Author(s):  
Rosana B. R. Ferreira ◽  
Yanet Valdez ◽  
Brian K. Coombes ◽  
Subash Sad ◽  
Joost W. Gouw ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Bacterial Colonization ◽  
Sub Saharan Africa ◽  
Secretory Iga ◽  
Effective Vaccine ◽  
High Morbidity ◽  
Content Type ◽  
Highly Effective ◽  
Serovar Typhimurium ◽  
Effective Component

ABSTRACTNontyphoidalSalmonella enterica(NTS) infections are a major burden to global public health, as they lead to diseases ranging from gastroenteritis to systemic infections and there is currently no vaccine available. Here, we describe a highly effective component vaccine againstS. entericaserovar Typhimurium in both gastroenteritis and systemic murine infection models. We devised an approach to generate supernatants ofS. entericaserovar Typhimurium, an organism that is highly abundant in virulence factors. Immunization of mice with this supernatant resulted in dramatic protection against a challenge with serovar Typhimurium, showing increased survival in the systemic model and decreased intestinal pathology in the gastrointestinal model. Protection correlated with specific IgA and IgG levels in the serum and specific secretory IgA levels in the feces of immunized mice. Initial characterization of the protective antigens in the bacterial culture supernatants revealed a subset of antigens that exhibited remarkable stability, a highly desirable characteristic of an effective vaccine to be used under suboptimal environmental conditions in developing countries. We were able to purify a subset of the peptides present in the supernatants and show their potential for immunization of mice against serovar Typhimurium resulting in a decreased level of colonization. This component vaccine shows promise with regard to protecting against NTS, and further work should significantly help to establish vaccines against these prevalent infections.IMPORTANCESalmonella entericainfections other than typhoid and paratyphoid fever are a major global health burden, as they cause high morbidity and mortality worldwide. Strategies that preventSalmonella-related diseases are greatly needed, and there is a significant push for the development of vaccines against nontyphoidalSalmonella entericaserovars. In this work, we describe anS. Typhimurium supernatant-derived vaccine that is effective in reducing bacterial colonization in mouse models of gastroenteritis as well as invasive disease. This is a component vaccine that shows high stability to heat, a feature that is important for use under suboptimal conditions, such as those found in sub-Saharan Africa.

scholarly journals The Role of Interleukine-10 and Interferon-γ as Potential Markers of the Evolution of African Swine Fever Virus Infection in Wild Boar

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 757
Author(s):  
Sandra Barroso-Arévalo ◽  
Jose A. Barasona ◽  
Estefanía Cadenas-Fernández ◽  
José M. Sánchez-Vizcaíno
Keyword(s):  
Wild Boar ◽  
Vaccine Candidate ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Interferon Γ ◽  
Fever Virus ◽  
Control Group ◽  
Challenge Virus ◽  
Ifn Γ

African swine fever virus (ASFv) is one of the most challenging pathogens to affect both domestic and wild pigs. The disease has now spread to Europe and Asia, causing great damage to the pig industry. Although no commercial vaccine with which to control the disease is, as yet, available, some potential vaccine candidates have shown good results in terms of protection. However, little is known about the host immune mechanisms underlying that protection, especially in wild boar, which is the main reservoir of the disease in Europe. Here, we study the role played by two cytokines (IL-10 and IFN-γ) in wild boar orally inoculated with the attenuated vaccine candidate Lv17/WB/Rie1 and challenged with a virulent ASFv genotype II isolate. A group of naïve wild boar challenged with the latter isolate was also established as a control group. Our results showed that both cytokines play a key role in protecting the host against the challenge virus. While high levels of IL-10 in serum may trigger an immune system malfunctioning in challenged animals, the provision of stable levels of this cytokine over time may help to control the disease. This, together with high and timely induction of IFN-γ by the vaccine candidate, could help protect animals from fatal outcomes. Further studies should be conducted in order to support these preliminary results and confirm the role of these two cytokines as potential markers of the evolution of ASFV infection.

scholarly journals A Whole Virion Vaccine for COVID-19 Produced via a Novel Inactivation Method and Preliminary Demonstration of Efficacy in an Animal Challenge Model

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 340
Author(s):  
Izabela K Ragan ◽  
Lindsay M Hartson ◽  
Taru S Dutt ◽  
Andres Obregon-Henao ◽  
Rachel M Maison ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Rapid Development ◽  
Neutralizing Antibody ◽  
Emerging Diseases ◽  
Effective Vaccine ◽  
Preliminary Evaluation ◽  
Sequencing Data ◽  
Post Challenge ◽  
Vaccine Candidates ◽  
The Impact

The COVID-19 pandemic has generated intense interest in the rapid development and evaluation of vaccine candidates for this disease and other emerging diseases. Several novel methods for preparing vaccine candidates are currently undergoing clinical evaluation in response to the urgent need to prevent the spread of COVID-19. In many cases, these methods rely on new approaches for vaccine production and immune stimulation. We report on the use of a novel method (SolaVAX) for production of an inactivated vaccine candidate and the testing of that candidate in a hamster animal model for its ability to prevent infection upon challenge with SARS-CoV-2 virus. The studies employed in this work included an evaluation of the levels of neutralizing antibody produced post-vaccination, levels of specific antibody sub-types to RBD and spike protein that were generated, evaluation of viral shedding post-challenge, flow cytometric and single cell sequencing data on cellular fractions and histopathological evaluation of tissues post-challenge. The results from this preliminary evaluation provide insight into the immunological responses occurring as a result of vaccination with the proposed vaccine candidate and the impact that adjuvant formulations, specifically developed to promote Th1 type immune responses, have on vaccine efficacy and protection against infection following challenge with live SARS-CoV-2. This data may have utility in the development of effective vaccine candidates broadly. Furthermore, the results of this preliminary evaluation suggest that preparation of a whole virion vaccine for COVID-19 using this specific photochemical method may have potential utility in the preparation of one such vaccine candidate.

scholarly journals A Novel and Efficient High-Yield Method for Preparing Bacterial Ghosts

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 420
Author(s):  
Yi Ma ◽  
Liu Cui ◽  
Meng Wang ◽  
Qiuli Sun ◽  
Kaisheng Liu ◽  
...  
Keyword(s):  
Large Scale ◽  
Expression System ◽  
High Yield ◽  
Wild Type ◽  
High Quality ◽  
Efficient Protection ◽  
Bacterial Ghosts ◽  
Cell Envelopes ◽  
Extracellular Structures ◽  
First Time

Bacterial ghosts (BGs) are empty cell envelopes possessing native extracellular structures without a cytoplasm and genetic materials. BGs are proposed to have significant prospects in biomedical research as vaccines or delivery carriers. The applications of BGs are often limited by inefficient bacterial lysis and a low yield. To solve these problems, we compared the lysis efficiency of the wild-type protein E (EW) from phage ΦX174 and the screened mutant protein E (EM) in the Escherichia coli BL21(DE3) strain. The results show that the lysis efficiency mediated by protein EM was improved. The implementation of the pLysS plasmid allowed nearly 100% lysis efficiency, with a high initial cell density as high as OD600 = 2.0, which was higher compared to the commonly used BG preparation method. The results of Western blot analysis and immunofluorescence indicate that the expression level of protein EM was significantly higher than that of the non-pLysS plasmid. High-quality BGs were observed by SEM and TEM. To verify the applicability of this method in other bacteria, the T7 RNA polymerase expression system was successfully constructed in Salmonella enterica (S. Enterica, SE). A pET vector containing EM and pLysS were introduced to obtain high-quality SE ghosts which could provide efficient protection for humans and animals. This paper describes a novel and commonly used method to produce high-quality BGs on a large scale for the first time.

scholarly journals Adaptation of the Endogenous Salmonella enterica Serovar Typhi clyA-Encoded Hemolysin for Antigen Export Enhances the Immunogenicity of Anthrax Protective Antigen Domain 4 Expressed by the Attenuated Live-Vector Vaccine Strain CVD 908-htrA

2004 ◽  
Vol 72 (12) ◽  
pp. 7096-7106 ◽  
Author(s):  
James E. Galen ◽  
Licheng Zhao ◽  
Magaly Chinchilla ◽  
Jin Yuan Wang ◽  
Marcela F. Pasetti ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Fluorescent Protein ◽  
Protective Antigen ◽  
Expression System ◽  
Dna Encoding ◽  
Protein Fusion ◽  
Vector Vaccine ◽  
Interleukin 5 ◽  
Export System ◽  
Domain 4

ABSTRACT Bacterial live-vector vaccines aim to deliver foreign antigens to the immune system and induce protective immune responses, and surface-expressed or secreted antigens are generally more immunogenic than cytoplasmic constructs. We hypothesize that an optimum expression system will use an endogenous export system to avoid the need for large amounts of heterologous DNA encoding additional proteins. Here we describe the cryptic chromosomally encoded 34-kDa cytolysin A hemolysin of Salmonella enterica serovar Typhi (ClyA) as a novel export system for the expression of heterologous antigens in the supernatant of attenuated Salmonella serovar Typhi live-vector vaccine strains. We constructed a genetic fusion of ClyA to the reporter green fluorescent protein and showed that in Salmonella serovar Typhi CVD 908-htrA, the fusion protein retains biological activity in both domains and is exported into the supernatant of an exponentially growing live vector in the absence of detectable bacterial lysis. The utility of ClyA for enhancing the immunogenicity of an otherwise problematic antigen was demonstrated by engineering ClyA fused to the domain 4 (D4) moiety of Bacillus anthracis protective antigen (PA). A total of 11 of 15 mice immunized intranasally with Salmonella serovar Typhi exporting the protein fusion manifested fourfold or greater rises in serum anti-PA immunoglobulin G, compared with only 1 of 16 mice immunized with the live vector expressing cytoplasmic D4 (P = 0.0002). In addition, the induction of PA-specific gamma interferon and interleukin 5 responses was observed in splenocytes. This technology offers exceptional versatility for enhancing the immunogenicity of bacterial live-vector vaccines.

scholarly journals Passive Immunization with Recombinant Antibody VLRB-PirAvp/PirBvp—Enriched Feeds against Vibrio parahaemolyticus Infection in Litopenaeus vannamei Shrimp

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
Jassy Mary S. Lazarte ◽  
Young Rim Kim ◽  
Jung Seok Lee ◽  
Jin Hong Chun ◽  
Si Won Kim ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Recombinant Antibody ◽  
Expression System ◽  
Passive Immunization ◽  
Control Group ◽  
Suitable Alternative ◽  
Shrimp Feed ◽  
A Cell ◽  
Acute Hepatopancreatic Necrosis Disease ◽  
Shrimp Farms

The causative agent of acute hepatopancreatic necrosis disease (AHPND) is the bacterium, Vibrio parahaemolyticus, which secretes toxins into the gastrointestinal tract of its host. Vibrio parahaemolyticus toxins A and B (PirAvp/PirBvp) have been implicated in the pathogenesis of this disease, and are, therefore, the focus of studies developing treatments for AHPND. We previously produced recombinant antibodies based on the hagfish variable lymphocyte receptor B (VLRB) capable of neutralizing some viruses, suggesting that this type of antibody may have a potential application for treatment of AHPND. Here, recombinant PirAvp/PirBvp, produced using a bacterial expression system, were used as antigens to screen a hagfish VLRB cDNA library to obtain PirAvp/PirBvp-specific antibodies. A cell line secreting these antibodies was established by screening and cloning the DNA extracted from hagfish B cells. Supernatants collected from cells secreting the PirAvp/PirBvp antibodies were collected and concentrated, and used to passively immunize shrimp to neutralize the toxins PirAvp or PirBvp associated with AHPND. Briefly, 10 μg of PirAvp and PirBvp antibodies, 7C12 and 9G10, respectively, were mixed with the shrimp feed, and fed to shrimp for three days consecutive days prior to experimentally infecting the shrimp with V. parahaemolyticus (containing toxins A and B), and resulting mortalities recorded for six days. Results showed significantly higher level of survival in shrimp fed with the PirBvp-9G10 antibody (60%) compared to the group fed the PirAvp-7C12 antibody (3%) and the control group (0%). This suggests that VLRB antibodies may be a suitable alternative to immunoglobulin-based antibodies, as passive immunization treatments for effective management of AHPND outbreaks within shrimp farms.

scholarly journals PREPARATION AND EVALUATION OF CHEMICALLY INACTIVATED SALMONELLA ENTERITIDIS VACCINE IN CHICKENS

2017 ◽  
Vol 10 (11) ◽  
pp. 341
Author(s):  
Mounir M El-safty ◽  
Hala Mahmoud ◽  
Eman Sa Zaki ◽  
Howaida I Abd-alla
Keyword(s):  
Immune Responses ◽  
Salmonella Enteritidis ◽  
Serum Antibody ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Chemically Induced ◽  
Before And After ◽  
Group A ◽  
Group B ◽  
Cell Envelopes

  Objective: Salmonella enteritidis ghosts (SEGs) is a non-living empty bacterial cell envelopes which were generated using a different concentration of sodium hydroxide (NaOH) 6.4 mg/mL and evaluated as a vaccine candidate in specific pathogen-free (SPF) chicken. SEGs have been produced by chemical-mediated lysis and evaluated the potential efficacy of chemically induced SEG vaccine and its ability to induce protective immune responses against virulent S. enteritidis challenge in SPF chickens.Methods: SPF chickens were divided into three groups: Group A (non-vaccinated control), Group B (vaccinated with prepared vaccine), and Group C (vaccinated with commercial vaccine).Results: Vaccination of SPF chicken with SEGs induced higher immune responses before and after virulent challenge. SPF chicken vaccinated with SEGs showed increasing in serum enzyme-linked immunosorbent assay (ELISA) antibodies. During the vaccination period, Groups B and C showed higher serum antibody titer compared to Group A. The minimal inhibitory concentration (MIC) of NaOH was capable of inducing non-living SEGs, and it has successfully generated non-living SEGs by MIC of NaOH.Conclusion: It is a one-step process which means easy manufacturing and low production cost compared to protein E-mediated lysis method. Chemically induced SEG vaccine is a highly effective method for inducing protective immunity. This study strongly suggests that SEGs will be a permissive vaccine, as the method of inhibition of S. enteritidis was safe and cheaper than other methods, and it gave a good protection.

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