Variable Levels Of Protection Research Articles

Comparative study of the effects of Montanide™ ISA 763A VG and ISA 763B VG adjuvants on the immune response against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus)

Streptococcus agalactiae is regarded as a major bacterial pathogen of farmed fish, with outbreaks in Nile tilapia causing significant losses. Vaccination is considered the most suitable method for disease control in aquaculture, with the potential to prevent such outbreaks if highly efficacious vaccines are available for use. Several vaccines have been produced to protect against S. agalactiae infection in tilapia, including inactivated vaccines, live attenuated vaccines, and subunit vaccines, with variable levels of protection seen. Two commercial adjuvants, Montanide™ ISA 763A VG and ISA 763B VG, have been developed recently and designed to improve the safety and efficacy of oil-based emulsions delivered by intraperitoneal injection. In particular, their mode of action may help identify and stimulate particular immunological pathways linked to the intended protective response, which is an important tool for future vaccine development. Therefore, this study aimed to characterize the potential of two adjuvanted-bacterial vaccines against S. agalactiae (SAIV) comparatively, to determine their usefulness for improving protection and to analyse the immune mechanisms involved. Nile tilapia were divided into four groups: 1) fish injected with PBS as a control, 2) fish injected with the SAIV alone, 3) fish injected with the SAIV + Montanide™ ISA 763A VG, and 4) fish injected with the SAIV + Montanide™ ISA 763B VG. Following immunization selected innate immune parameters were analysed, including serum lysozyme, myeloperoxidase, and bactericidal activity, with significantly increased levels seen after immunization. Cytokines associated with innate and adaptive immunity were also studied, with expression levels of several genes showing significant up-regulation, indicating good induction of cell-mediated immune responses. Additionally, the specific IgM antibody response against S. agalactiae was determined and found to be significantly induced post-vaccination, with higher levels seen in the presence of the adjuvants. In comparison to the protection seen with the unadjuvanted vaccine (61.29% RPS), both Montanide™ ISA 763A VG and Montanide™ ISA 763B VG improved the RPS, to 77.42% and 74.19% respectively. In conclusion, Montanide™ ISA 763A VG and Montanide™ ISA 763B VG have shown potential for use as adjuvants for fish vaccines against streptococcosis, as evidenced by the enhanced immunoprotection seen when given in combination with the SAIV vaccine employed in this study.

High‐resolution drone imagery reveals drivers of fine‐scale giant otter habitat selection in the land‐water interface

AbstractNeotropical freshwater habitats are particularly sensitive to degradation by human activity. Piscivorous semi‐aquatic freshwater megafauna inhabit both the terrestrial and aquatic mediums and thus may be good indicators of wetland habitat quality. However, the drivers of their space use at the terrestrial and aquatic landscape levels are not well understood. We studied the spatial behavior and habitat use of giant otters in Madre de Dios, Peru, inhabiting areas with variable levels of protection. We combined unmanned aerial vehicle (UAV) and satellite images to develop different terrestrial and water‐associated land cover variables. We tested the influence of these predictors on giant otter habitat use at multiple spatial scales, comparing used and available locations. Giant otters favored bank areas with dense forest canopy cover. In the aquatic medium, giant otters showed positive selection for open water and fallen logs and avoided floating vegetation. These findings may be explained by preference for optimal fish habitat to maximize foraging yield and bank areas that provide more cover from predators and higher quality denning locations. Variables developed from UAV images outperformed satellite‐derived variables. Despite recent signs of deforestation in lake banks in unprotected areas, spatial model predictions indicated that unprotected oxbow lakes did not differ in their habitat suitability from protected freshwater habitats. Management implications of our findings include identification of factors driving habitat suitability to guide policy and decisions regarding protection or restoration of oxbow lake ecosystems to support giant otter populations. In addition, we demonstrate that UAVs have value in complementing satellite‐derived images and providing a cost‐effective methodology to assess habitat quality for semi‐aquatic species at the land‐water interface.

MP02-11 CHARACTERIZATION OF COMPLEMENT RESISTANCE FACTOR TRAT ENCODED IN DRUG RESISTANCE PLASMIDS OF UROPATHOGENIC ESCHERICHIA COLI

You have accessJournal of UrologyCME1 May 2022MP02-11 CHARACTERIZATION OF COMPLEMENT RESISTANCE FACTOR TRAT ENCODED IN DRUG RESISTANCE PLASMIDS OF UROPATHOGENIC ESCHERICHIA COLI Chae Hee Lim, Aryana Bhati, Katelyn Lott, Jazmyn Whitfield, John Land, and Tatyana Sysoeva Chae Hee LimChae Hee Lim More articles by this author , Aryana BhatiAryana Bhati More articles by this author , Katelyn LottKatelyn Lott More articles by this author , Jazmyn WhitfieldJazmyn Whitfield More articles by this author , John LandJohn Land More articles by this author , and Tatyana SysoevaTatyana Sysoeva More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002514.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The TraT protein is a multifunctional virulence factor that is encoded by conjugative F-like plasmids. A majority of multidrug-resistant uropathogenic Escherichia coli (UPEC) carry F-like plasmids and thus encode for this TraT factor. In non-pathogenic E. coli, TraT is a highly expressed outer membrane lipoprotein that protects the bacterial cell from excessive rounds of plasmid transfer, from a few bacteriophages, and from the host innate immune response via serum complement killing. Our objectives in this study were (1) to measure the protective effect of TraT in UPEC background and (2) to establish whether extracellular TraT domain is sufficient to provide serum resistance. METHODS: We used conjugation to transfer the model F’ plasmid in different E. coli backgrounds. Recombinant extracellular soluble domain TraT33-244 was purified from BL21(DE3) E. coli strain using Ni-affinity chromatography. Exponentially growing E. coli cultures with and without traT-encoding plasmids or the purified TraT domain were subjected to different doses of blood serum for 2 hours at 37°C. Viable cells were quantified as colony forming units by plating serial dilutions at 0 and 2 hours after addition of serum. RESULTS: The traT-encoding plasmid provides variable level of protection that depends on serum type, bacterial cells, time, and ratios of bacteria and serum, and can reach several orders of magnitude. We have developed a method of expression and purification of soluble TraT33-244 protein and showed that this extracellular domain forms stable oligomers in solution with five-to-six subunits. Testing this purified extracellular domain in serum resistance assays revealed that it is insufficient to exhibit the full protective action of TraT. CONCLUSIONS: In this study, we measured the protective effect of traT-encoding plasmid F’ in model E. coli strains, which displayed strong but variable serum resistance. The extracellular soluble domain of TraT protein oligomerizes, but does not strongly protect against serum killing when added to bacterial cells in trans. These results suggest that membrane localization, N-terminus, or lipidation itself are important for function of the TraT factor. Overall, this study sets the stage for further investigation into the mechanism of how TraT assists UPEC bacteria in evading innate immune responses within the host organism. Source of Funding: The University of Alabama in Huntsville startup funds to Tatyana Sysoeva © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e14 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Chae Hee Lim More articles by this author Aryana Bhati More articles by this author Katelyn Lott More articles by this author Jazmyn Whitfield More articles by this author John Land More articles by this author Tatyana Sysoeva More articles by this author Expand All Advertisement PDF DownloadLoading ...

Location matters in RSV protection

In this issue of Cell Host & Microbe, Zohar etal., 2022 show that immunization of non-human primates with six different candidate respiratory syncytial virus vaccines resulted in distinct antibody profiles and variable levels of protection. Using a systems serology approach, they identified compartment-specific antibody-mediated correlates of protection.

Penicillin-binding protein PBP2a provides variable levels of protection toward different β-lactams in Staphylococcus aureus RN4220.

Methicillin‐resistant Staphylococcus aureus (MRSA) is resistant to most β‐lactams due to the expression of an extra penicillin‐binding protein, PBP2a, with low β‐lactam affinity. It has long been known that heterologous expression of the PBP2a‐encoding mecA gene in methicillin‐sensitive S. aureus (MSSA) provides protection towards β‐lactams, however, some reports suggest that the degree of protection can vary between different β‐lactams. To test this more systematically, we introduced an IPTG‐inducible mecA into the MSSA laboratory strain RN4220. We confirm, by growth assays as well as single‐cell microfluidics time‐lapse microscopy experiments, that PBP2a expression protects against β‐lactams in S. aureus RN4220. By testing a panel of ten different β‐lactams, we conclude that there is also a great variation in the level of protection conferred by PBP2a. Expression of PBP2a resulted in an only fourfold increase in minimum inhibitory concentration (MIC) for imipenem, while a 32‐fold increase in MIC was observed for cefaclor and cephalexin. Interestingly, in our experimental setup, PBP2a confers the highest protection against cefaclor and cephalexin—two β‐lactams that are known to have a high specific affinity toward the transpeptidase PBP3 of S. aureus. Notably, using a single‐cell microfluidics setup we demonstrate a considerable phenotypic variation between cells upon β‐lactam exposure and show that mecA‐expressing S. aureus can survive β‐lactam concentrations much higher than the minimal inhibitory concentrations. We discuss possible explanations and implications of these results including important aspects regarding treatment of infection.

The BCGΔBCG1419c strain, which produces more pellicle in vitro, improves control of chronic tuberculosis in vivo

Mycobacterium tuberculosis (Mtb) has been a threat to humans since ancient times, and it is the main causative agent of tuberculosis (TB). Until today, the only licensed vaccine against Mtb is the live attenuated M. bovis Bacillus Calmette-Guérin (BCG), which has variable levels of protection against the pulmonary form of infection. The quest for a new vaccine is a priority given the rise of multidrug-resistant Mtb around the world, as well as the tremendous burden imposed by latent TB. The objective of this study was to evaluate the immunogenicity and capacity of protection of a modified BCG strain (BCGΔBCG1419c) lacking the c-di-GMP phosphodiesterase gene BCG1419c, in diverse mice models. In a previous report, we have shown that BCGΔBCG1419c was capable of increasing biofilm production and after intravenous infection of immunocompetent mice; this strain persisted longer in lungs than parental BCG Pasteur. This led us to hypothesize that BCGΔBCG1419c might therefore possess some advantage as vaccine candidate. Our results in this report indicate that compared to conventional BCG, vaccination with BCGΔBCG1419c induced a better activation of specific T-lymphocytes population, was equally effective in preventing weight loss despite being used at lower dose, reduced tissue damage (pneumonic scores), increased local IFNγ+ T cells, and diminished bacterial burden in lungs of BALB/c mice infected intratracheally with high dose Mtb H37Rv to induce progressive TB. Moreover, vaccination with BCGΔBCG1419c improved resistance to reactivation after immunosuppression induced by corticosterone in a murine model of chronic infection similar to latent TB. Furthermore, despite showing increased persistence in immunocompetent mice, BCGΔBCG1419c was as attenuated as parental BCG in nude mice. To our knowledge, this is the first demonstration that a modified BCG vaccine candidate with increased pellicle/biofilm production has the capacity to protect against Mtb challenge in chronic and reactivation models of infection.

Efficacy Evaluation of an Inactivated Duck Tembusu Virus Vaccine.

To evaluate the potential use of an inactivated virus-based vaccine for the control and prevention of the newly emerged duck Tembusu virus infection in China, a duck Tembusu virus isolate, Tembusu-HB, was propagated in 12-day-old duck embryos and inactivated by treatment with formaldehyde. The inactivated viral antigen was emulsified with mineral oil, and five batches of the vaccine were manufactured. The immunogenicity and protection efficacy of the vaccine were evaluated in Beijing ducks and Beijing white geese. Results showed that more than 80% of immunized ducks were protected against virulent virus challenge after two intramuscular or subcutaneous injections of the inactivated vaccine, as evidenced by the negative virus isolation results. The protection is also correlated with a positive virus-specific antibody response as detected by ELISA. In contrast, none of the control ducks and geese had any detectable antibody response. Virus was isolated from all control ducks and geese after virulent virus challenge. Interestingly, a variable level of protection (20%-80%) was observed in Beijing white geese immunized twice with the same batches of vaccine, suggesting a species-specific effect of the vaccine. Overall, the results clearly suggest that the inactivated duck Tembusu virus vaccine is immunogenic and provides protection against virulent virus challenge.

Oral cholera vaccine—for whom, when, and why?

The search for a safe, effective, well tolerated, low cost vaccine against the ancient cholera enemy has been ongoing since the 19th century and has been revitalized in the past two decades since the advent of recombinant technology. Large-scale field trials have readily demonstrated the tolerability and safety of oral cholera vaccine in various forms. Variable levels of protection have been shown and one challenge has been to demonstrate whether this is a cost effective treatment in differing environments including its use in endemic and epidemic areas as well as for travelers. A review of recent literature was undertaken to assess the effectiveness and uses of currently available oral cholera vaccine. While the evidence does not support the creation of formal guidelines, some clear recommendations can be made. There is undoubtedly the potential to reduce the burden of illness both in endemic and epidemic situations. For travelers, certain higher risk groups may benefit from protection against cholera. More significantly, the short term cross-protection afforded by whole cell, B subunit (WC BS) oral cholera vaccine formulations against enterotoxigenic E. coli, (ETEC), the commonest causative agent of traveler's diarrhoea, may prove to be the most important raison d'être.

Protection against Leishmania major challenge infection in mice vaccinated with live recombinant parasites expressing a cytotoxic gene.

A "suicide" system based on thymidine kinase-ganciclovir combination was developed and tested in a Leishmania major experimental model. Susceptible BALB/c mice were infected with L. major expressing the thymidine kinase gene of herpes simplex virus type 1 and treated for 2 consecutive weeks with 7.5 mg/kg/day ganciclovir at different times from the initial infection. Ganciclovir treatment at varying times after infection had different effects on the outcome of disease. A complete inhibition of intracellular parasites was obtained in mice treated 1 or 4 days after infection, whereas ganciclovir administration 2 weeks later resulted in the control of infection only when the drug was provided. Variable levels of protection, from partial to total, against challenge infection with virulent L. major were observed, depending on the timing of ganciclovir treatment. The thymidine kinase-ganciclovir approach represents an excellent experimental model to control Leishmania infection and to evaluate the immunologic response of the host.