Browsing by Subject "Vaccine"
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Item Cloning, expression, and purification of Burkholderia protein targets for diagnostic and vaccine development(2012-05) McCaul, Kate Christina; Brown, Katherine A.; Kitto, George B.Burkholderia pseudomallei and Burkholderia mallei cause the diseases melioidosis and glanders, respectively. These diseases are endemic mainly in southeastern Asia and northern Australia, but they also pose a bioterrorism threat in the developed world. These diseases have high mortality, partially due to the lack of vaccines and rapid, accurate diagnostic assays. The work discussed here represents a part of a larger project to develop a dependable diagnostic assay for use in both developing endemic areas and the developed world, as well as a subunit vaccine to protect against disease. In this study, several proteins from B. pseudomallei, B. mallei, and the closely related but less virulent B. thailandensis have been cloned, expressed and purified in order to develop highly sensitive and specific diagnostic reagents for the detection of B. pseudomallei and B. mallei in infected patient samples. Protein targets expressed in this study were also used in subunit vaccine development for melioidosis and glanders.Item Enhancing Chicken Mucosal IgA Response Against Clostridium Perfringens a-toxin(2012-07-27) Chen, Chang-Hsin 1977-Necrotic enteritis (NE) is an economically important enteric disease of broiler chicken primarily caused by a-toxin (Cpa) secreted by C. perfringens type A. Mice immunized with recombinant C-terminal domain of Cpa (CpaCD) had transient and fewer localized lesions upon challenge with C. perfringens type A. These results demonstrate the usefulness of CpaCD as an immunogen for vaccine development against NE for chickens. Chicken CD40 (chCD40) is mainly expressed on the surface of chicken antigen-presenting cells (APCs), and the interaction of chCD40 and chCD40L (natural ligand for chCD40) provides crucial activation signals for chicken B-cells. A hypothesis was proposed that in ovo vaccination with an adenovirus-vectored CpaCD vaccine capable of targeting immunogen to APCs through the CD40 pathway will improve protection against NE in chickens. One agonistic monoclonal anti-chCD40 antibody (designated 2C5) was produced and characterized. 2C5 not only detected expression of chCD40 on chicken APCs, but also induced NO synthesis in chicken HD11 macrophages and enhanced proliferation of serum-starved chicken DT40 B-cells. This demonstrated substantial functional equivalence of 2C5 with chCD40L. The potential of 2C5 as an immunological adjuvant was further assessed by targeting a hapten to chicken APCs in hopes of enhancing an effective IgG response. Seven-week old chickens were immunized subcutaneously once with a complex consisting of 2C5 and peptide, and relative quantification of the peptide-specific IgG response showed that this complex was able to elicit a strong IgG response as early as four days post-immunization. This demonstrates that CD40-targeting antigen to chicken APCs can significantly enhance antibody responses and induce immunoglobulin isotype-switching. An agonistic anti-chCD40 single-chain variable fragment (designated DAG1) was combined with an adenoviral delivery system to create a vaccine, Ad-(DAG1-Cp aCD-FLAG), for in ovo administration. The efficacy of in ovo vaccination of broilers with Ad-(DAG1-Cp aCD-FLAG) in controlling NE was evaluated by C. perfringens type A challenge at 18 days post-hatch. Neither statistically significant IgA / IgG response nor protection against C. perfringens type A challenge was found in the vaccinated birds. These preliminary data suggest that a super-optimal dose of Ad-(DAG1-Cp aCD-FLAG) may be the main issue, because Cpa-specific B-cells may undergo apoptosis through the CD40 pathway.Item Human adenovirus serotype 5 vaccines : routes of delivery and formulations for successful immunization(2010-08) Dekker, Joseph Dylan; Tucker, Philip W.; Kobinger, Gary P.; Otto, Glen; Sullivan, Christopher S.; Huibregtse, Jon M.Delivery of medicinal products to specific targets can be aided by utilizing different routes of administration. Particular routes may be advantageous when delivering products designed for therapeutic drug delivery, gene therapy, or vaccination. Vaccine candidates must remain stable, be delivered to their proper compartments, and promote sufficient immune responses to their delivered antigens, properties that can be modulated by formulation, adjuvants, and alternate routes of administration. Recently, the nasal passageway has been recognized as a promising route, as mucosally delivered vaccines have the advantage of inducing protection at both mucosal surfaces, a common site of infection, and systemically. Human adenovirus serotype 5 (Ad5) is a candidate vaccine vector capable of being delivered through several routes and inducing strong immune responses to its delivered transgene. The studies presented include vaccination strategies following different routes of administration with various formulation components to determine the ability of Ad5 to deliver its transgene and induce immune responses. The first study screens formulation candidates’ effects on an Ad5-based vaccine’s transduction in vitro, cellular and humoral immune responses in vivo, and efficacy upon challenge in mice. Screening formulation candidates in vitro can eliminate ineffective formulations, thereby limiting animal testing. An Ad5-based Ebola virus vaccine delivered in a combination of mannitol, sucrose, and the surfactant, pluronic F68, improves survival against lethal Ebola challenge in a mouse model compared to delivery in PBS alone. The second study tests the effect of an intravenously delivered Ad5-based vaccine complexed with anti-Ad5 neutralizing antibodies on cellular and humoral immune responses. Different antibody ratios complexed to the Ad5 vector are able to induce disparate cellular and humoral responses. Ratios initiating a strong humoral response towards the Ad5 vector correlate with a reduction of the humoral response against the transgene and few transgene targeted effector T cells. Accordingly, ratios leading to minor humoral responses to the Ad5 vector resulted in stronger humoral responses to the transgene and a strong effector memory T cell response. Taken together, these studies provide insight on how to achieve necessary immune responses in vaccine protocols by testing routes of administration, formulations, and surface modifications of the Ad5 vector.Item Immunomodulatory Effects of Probiotic and Anticoccidial Treatments in Broiler Chickens(2012-10-19) Stringfellow, KendreFour experiments evaluated the impact of probiotic administration on the immune response of broilers vaccinated with a live coccidiosis vaccine. Experiment one showed that probiotic administration increased heterophil and monocyte oxidative burst, and lymphocyte proliferation at multiple time points. In experiment two, probiotic + vaccine increased heterophil and monocyte oxidative burst on d 15 when compared with the negative controls. Overall, vaccine administration alone showed the highest response when compared to all other treatments. In the second trial, all birds were exposed to Eimeria oocysts in the litter and oral gavaged. The results showed that probiotic + vaccine resulted in greater heterophil and monocyte oxidative burst levels on d 14 and 28 when compared to the negative controls. Increases in lymphocyte proliferation were also seen in the probiotic + vaccine and probiotic alone broilers on d 14 among other treatments. In experiment three, heterophil oxidative burst was increased (p <= 0.05) in the vaccine alone group, vaccine with probiotic group, and the ionophore with probiotic group, when compared to the negative control. Monocyte oxidative burst was increased (p <= 0.05) in the vaccine with probiotic group on d 36 and 43, compared to the negative control. Lymphocyte proliferation was greater (p <= 0.05) on d 22 and 36 in the ionophore with probiotic group, when compared to the negative control. Experiment four showed that liver AVBD 2 gene expression elevated (p <= 0.05) in the probiotic + vaccine group relative to the probiotic alone group. Ileum AVBD 2 gene expression was not affected among any of the treatments was evaluated. Liver AVBD 9 was demonstrated to have higher (p <= 0.05) gene expression in the vaccine group when compared to controls. When AVBD 9 gene expression was evaluated in the ileum, a decrease (p <= 0.05) was observed in all treatments compared to the control group. These data suggest that simultaneous administration of probiotics during coccidiosis vaccination or ionophore treatment has the ability to modulate the immune response at varying time points.Item Male perceptions of and attitudes toward the Human Papillomavirus vaccine : effective promotional strategies(2015-05) Ray, Rachelle Marie; Mackert, Michael; Love, BradThe Human Papillomavirus (HPV) is one of the most prevalent sexually transmitted diseases among American men and women. When first licensed by the United States Food and Drug Administration (FDA), the HPV vaccine was originally only approved for use in females ages 9-26 years. Promotional communications reflected this, using messaging strategies that effectively positioned the vaccine as a “women’s vaccination.” In 2010, the FDA approved the HPV vaccine for use in males ages 9-26, though advertising and marketing of the vaccine for this new population was limited. This study evaluated males’ knowledge of and attitudes toward HPV and the HPV vaccine, as well as message tactics for promotion of the HPV vaccine to male populations. Using an online survey and a convenience sampling technique, this study reached a young, highly educated sample of males within the “catch up” program age range. The results of the study indicated a basic understanding o HPV, but a limited understanding of the health-risks associated with the disease. Communication efforts using fact-based tactics were found to be the most effective at persuading males to seek vaccination.Item Overlooked casualties : stories of families affected by vaccine-preventable diseases(2012-05) Haelle, Tara Susan; Darling, Dennis Carlyle; Minutaglio, BillThe invention of the vaccine has been one of the greatest public health triumphs of the modern world. Each new vaccine has saved thousands - even millions - of lives worldwide, but this success has been fraught with controversy over the safety and even the effectiveness of vaccines. Vaccines have not always had a spotless safety record, but today’s vaccines are incredibly safe and continue to protect millions of people against diseases that have significantly declined or nearly disappeared from the developing world. It is this very success that has led many people to forget, or never discover, what those diseases are and how destructive they can be. This report tells the story of several families whose lives were deeply affected by vaccine-preventable diseases, accompanied with images that help tell their story. Following these stories is a broader discussion of the issues related to vaccines, the misunderstandings and misinformation that often circulate about them, a brief mention of their safety and efficacy, and a general discussion of many of the diseases they can prevent.Item Recent advances and challenges in antigen engineering & vaccine development(2014-05) Kornahrens, William Joseph; Maynard, Jennifer Anne, 1974-Vaccines play a vital role in public health by preventing infectious disease across the globe. Vaccine formulations represent a weakened form of a microbe or toxin that is injected into the human body to elicit an immune response, generating antibodies to protect against a future infection. To this day, it is a challenge to identify and engineer important antigens and epitopes to focus this immune response in a safe and effective manner. The example of Bordetella pertussis is used to highlight the problems and lessons learned in designing a vaccine for this global epidemic. In particular, this review will focus on the advantages and disadvantages of chemical versus genetic detoxification and whole cell versus acellular vaccines in the context of pertussis. The latter part of this review will provide a summary of general strategies, such as epitope mapping and manipulation, synthesis of truncated variants, reverse vaccinology, and structural vaccinology, that have been successful in addressing increasingly complex diseases. Collectively, these techniques provide an invaluable set of tools to focus the immune response by finding and engineering specific antigens and epitopes.Item Simultaneous, single-carrier delivery of antigens and immune-modulatory molecules to dendritic cells(2013-05) Dawson, Eileen Regina; Roy, Krishnendu; Peppas, Nicholas A., 1948-Immunotherapy as a means for cancer treatment has been investigated for over a century. While studies have been completed using different immunological strategies, development of a clinical therapeutic cancer vaccine has proven elusive. Recently, success has been seen with prophylactic vaccines for cancers with known viral origins (Gardasil® and Cervarix for Human Papiloma Virus). However, such strategies do not address the challenge in generating effective immune response against other tumor antigens, most of which are weakly immunogenic self-antigens. Tolerance to these self-antigens could ultimately limit the patient’s ability to mount an effective anti-tumor immune response. The US Food and Drug Administration recently approved the first DC cell-based cancer vaccine, Provenge®, for use in prostate cancer. This vaccine requires cell isolations from the patient as well as in vitro DC modifications, which ultimately leads to high cost as well as multiple procedures. However, results indicate that, on average, patients live only four months longer than those receiving a placebo. While this work remains important, and offers proof that priming DCs can improve the lifespan of a patient, it ultimately does not offer a long-term cure. Direct and highly efficient in vivo delivery of antigens to DCs could overcome the challenges associated with ex vivo DC manipulation and may offer a more scalable method for generating anti-tumor immunity. This research focuses on the development of novel formulations that allow simultaneous delivery of protein/peptide-based tumor antigens and immune-modulatory nucleic acids (siRNA and immune stimulatory CpG) to the same dendritic cells (DCs) in-vivo. Such formulations allow a synthetic immune-priming center to be created at the site of immunization and simultaneously deliver the tumor antigen to DCs and modulate their immune response through IL-10 silencing. Our hypothesis is that using such a DC-targeted dual delivery system we will be able to illicit strong T helper 1 (TH1) and Cytotxic T Lymphocyte (CTL) response in vivo against a wide array of tumor antigens. This can become a platform technology where the biomolecules (antigen and immunomodulatory agents) can be easily varied based on particular cancers.Item Vaccine formulation development : towards addressing major limitations of vaccines that are adjuvanted with aluminum salts(2013-12) Li, Xinran; Cui, ZhengrongMany vaccines require an adjuvant to induce a strong immune response. Aluminum–containing adjuvants have been approved by the United States Food and Drug Administration for human use for many years. There are two main aluminum-containing adjuvants, aluminum hydroxide and aluminum phosphate. Due to their favorable safety profile, aluminum-containing adjuvants have been widely used in human vaccines for decades. Many currently licensed and commercially available vaccines contain aluminum-containing adjuvants. However, aluminum-containing vaccine adjuvants suffer from two major limiting factors: (1) aluminum-containing adjuvants can only weakly or moderately potentiate antigen-specific antibody responses and are generally considered incapable of inducing cellular immune responses; (2) vaccines that contain aluminum-containing adjuvants require cold-chain refrigeration for storage and distribution, and may not be frozen, because freezing of the vaccine in dispersion causes irreversible coagulation that damages vaccines (e.g., loss in potency and stability). In this dissertation, the first limitation was addressed by reducing the size of the aluminum hydroxide from micrometers (3-10 micrometer) to nanometers of less than 200 nm, and the second limitation mentioned above was addressed by freeze-drying vaccines that contain aluminum salts as adjuvants into a dry powder using thin-film freeze-drying. In addition, using an improved experimental design, the vaccine adjuvant activities of nanoparticles of around 200 nm was compared to that of the nanoparticles of around 700 nm. The smaller 200 nm nanoparticles showed a more potent adjuvant activity than the larger nanoparticles. When dispersed in an aqueous medium, both aluminum hydroxide and aluminum phosphate are physically 1–20 micrometer particulates. There are data showing that particulate vaccine carriers of around 200 nm (or less) may be optimal in potentiating the immunogenicity of vaccines. Based on this finding, aluminum hydroxide nanoparticles of 112 nm were synthesized, and its adjuvant activity was compared to that of the traditional aluminum hydroxide adjuvant, which have particulates of 3-20 micrometer. Using ovalbumin and Bacillus anthracis protective antigen protein as model antigens, it was found that protein antigens adsorbed on the aluminum hydroxide nanoparticles induced stronger antigen-specific antibody responses than the same protein antigens adsorbed on the traditional aluminum hydroxide microparticles of around 9.3 µm. Importantly, the inflammation reactions induced by aluminum hydroxide nanoparticles in the injection sites were milder than that induced by microparticles. Simply reducing the particle size of the traditional aluminum hydroxide adjuvant in suspension from micrometers into nanometers represents a novel and effective approach to improve its potency. The second limitation was addressed by converting vaccines that contain an aluminum salt as an adjuvant from an aqueous dispersion into a dried powder using thin-film freeze-drying. There is evidence that aluminum-containing vaccines can be lyophilized to dry powders using high speed freezing methods. Thin-film freezing is a high speed freezing method with a freezing rate between 100 to 10,000 K/s, but the feasibility of using thin-film freeze-drying to freeze-dry vaccines that contain aluminum salts as adjuvants has not been tested before. In this dissertation, Using ovalbumin as a model protein antigen and aluminum hydroxide or aluminum phosphate as an adjuvant, it was confirmed that vaccines that are adjuvanted with aluminum hydroxide or aluminum phosphate can be freeze-dried with as low as 2% (w/v) of trehalose as a cryoprotectant by thin-film freeze-drying without causing vaccine aggregation while preserving the immunogenicity of the vaccine. Finally, the feasibility of using the thin-film freeze-drying method to freeze-drying vaccines that contain aluminum salts as adjuvants was further confirmed by drying a commercial aluminum salt-adjuvanted tetanus toxoid vaccine. Vaccines that contain aluminum salts as adjuvants may be converted to a dry powder using the thin-film freeze-drying method to avoid loss of potency due exposure to freezing conditions during transport and storage.Item Vaccine-adverse event association analysis on the VAERS database(2011-05) Ye, Na, 1983-; Powers, Daniel A.; Saar-Tsechansky, MaytalThe Vaccine Adverse Event Reporting System (VAERS) received thousands of reports of adverse events that occurred after vaccine administrations from the post-marketing vaccine safety surveillance. However, the causality between vaccines and reported adverse events cannot be taken for granted. In this report several data mining methods were applied to VAERS database that is coded in MedDRA terms to discover possible associations between vaccines and adverse events. Efforts were devoted to identify events that are reported more frequently after administering one vaccine than other vaccines using the following data mining techniques: relative ratio (RR), statistical significance (LogP), proportional reporting ratio (PRR), and screened PRR (SPRR). The vaccine-event combinations that ranked top in each method varied substantially among the methods. RR and PRR gave excessive weight to small counts of vaccine-event pairs, but SPRR was able to correct this weakness. There are only 33 vaccine-event pairs that were shared among the top 1,000 ranked in each method. Evaluating the properties of these data mining methods and exploring other methods will help improve vaccine safety surveillance.