Matching Items (6)
Filtering by
- Genre: Masters Thesis
- Creators: Arizona State University
- Status: Published
Description
ABSTRACT In terms of prevalence, human suffering and costs dengue infections are the most important arthropod-borne viral disease worldwide. Dengue virus (DENV) is a mosquito-borne flavivirus and the etiological agent of dengue fever and dengue hemorrhagic fever. Thus, development of a safe and efficient vaccine constitutes an urgent necessity. Besides the traditional strategies aim at generating immunization options, the usage of viral vectors to deliver antigenic stimulus in order to elicit protection are particularly attractive for the endeavor of a dengue vaccine. The viral vector (MVvac2) is genetically equivalent to the currently used measles vaccine strain Moraten, which adds practicality to my approach. The goal of the present study was to generate a recombinant measles virus expressing structural antigens from two strains of DENV (DENV2 and DENV4) The recombinant vectors replication profile was comparable to that of the parental strain and expresses either membrane bound or soluble forms of DENV2 and DENV4 E glycoproteins. I discuss future experiments in order to demonstrate its immunogenicity in our measles-susceptible mouse model.
ContributorsAbdelgalel, Rowida (Author) / Reyes del Valle, Jorge (Thesis advisor) / Hogue, Brenda (Committee member) / Frasch, Wayne D (Committee member) / Arizona State University (Publisher)
Created2013
Description
African Swine Fever (ASF), endemic in many African countries, is now spreading to other continents. Though ASF is capable of incurring serious economic losses in affected countries, no vaccine exists to provide immunity to animals. Disease control relies largely on rapid diagnosis and the implementation of movement restrictions and strict eradication programs. Developing a scalable, accurate and low cost diagnostic for ASF will be of great help for the current situation. CIM's 10K random peptide microarray is a new high-throughput platform that allows systematic investigations of immune responses associated with disease and shows promise as a diagnostic tool. In this study, this new technology was applied to characterize the immune responses of ASF virus (ASFV) infections and immunizations. Six sets of sera from ASFV antigen immunized pigs, 6 sera from infected pigs and 20 sera samples from unexposed pigs were tested and analyzed statistically. Results show that both ASFV antigen immunized pigs and ASFV viral infected pigs can be distinguished from unexposed pigs. Since it appears that immune responses to other viral infections are also distinguishable on this platform, it holds the potential of being useful in developing a new ASF diagnostic. The ability of this platform to identify specific ASFV antibody epitopes was also explored. A subtle motif was found to be shared among a set of peptides displaying the highest reactivity for an antigen specific antibody. However, this motif does not seem to match with any antibody epitopes predicted by a linear antibody epitope prediction.
ContributorsXiao, Liang (Author) / Sykes, Kathryn (Thesis advisor) / Zhao, Zhan-Gong (Committee member) / Stafford, Phillip (Committee member) / Arizona State University (Publisher)
Created2011
Description
Beliefs about change reflect how we understand phenomena and what kind of predictions we make for the future. Cyclical beliefs about change state that events are in a constant flux, and change is inevitable. Linear beliefs about change state that events happen in a non-fluctuating pattern and change is not commonplace. Cultural differences in beliefs about change have been documented across various domains, but research has yet to investigate how these differences may affect health status predictions. The present study addresses this gap by inducing different beliefs about change in a European-American college sample. Health status predictions were measured in terms of predicted likelihood of exposure to the flu virus, of contraction of the flu, and of receiving a flu vaccine. Most differences were observed among those who have a recent history of suffering from the flu. Among them, cyclical thinkers tended to rate their likelihood for exposure and contraction to be higher than linear thinkers. However, linear thinkers indicated that they were more likely to receive a flu vaccine. The different patterns suggest the possibility that cyclical beliefs may activate concepts related to cautionary behaviors or pessimistic biases, while linear beliefs may activate concepts related to taking action and exercising control over the environment. Future studies should examine the interplay between beliefs about change and the nature of the predicted outcome.
ContributorsKim, Summer Hyo Yeon (Author) / Kwan, Virginia S. Y. (Thesis advisor) / Neuberg, Steven L. (Committee member) / Cohen, Adam B. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Vaccines against the arthropod-borne dengue virus (DENV) are still commercially nonexistent. A subunit immunization strategy may be of value, especially if a safe viral vector acts as a biologically active adjuvant. The DENV envelope protein (E), the main target for neutralizing immune responses, has three conformational domains. The immunoglobulin-like and independently folding domain III (DIII) contains epitopes that elicit highly specific neutralizing antibodies. The hepatitis B small surface antigen (HBsAg, S) was used as a scaffold to display DENV 2 DIII on a virus-like particle (VLP). A measles virus (MV) was engineered to vector HBsAg and the hybrid glycoprotein DIII-HBsAg in two different loci (DIII-S). Despite the relatively deleterious effect on replication caused by the insertion of two transcription cassettes, the recombinant virus MVvac2(DIII-S,S)P induced the secretion of DIII-S hybrid VLP with a similar sucrose density as HBsAg particles (1.10-1.12g/ml) and peaked at 48 h post-infection producing 1.3x106 TCID50/ml infectious MV units in vitro. A second recombinant virus, MVvac2(DIII-S)N, was engineered to vector only the hybrid DIII-S. However, it did not induce the secretion of hybrid HBsAg particles in the supernatant of infected cells. The immunogenicity of the recombinant viruses was tested in a MV-susceptible small animal model, the experimental group which received two 105 TCID50 I.P. doses of MVvac2(DIII-S,S)P in a 28 day interval developed a robust immune response against MV (1:1280), HBsAg (787 mIU/ml) and DENV2 (Log10 neutralization index of 1.2) on average. In summary, it is possible to display DENV E DIII on hybrid HBsAg particles vectored by MV that elicit an immune response. This forms the basis for a potential vaccine platform against DENV.
ContributorsHarahap, Indira (Author) / Reyes del Valle, Jorge (Thesis advisor) / Hogue, Brenda G (Thesis advisor) / Lake, Douglas (Committee member) / Mason, Hugh (Committee member) / Arizona State University (Publisher)
Created2015
Description
Vaccinations are important for preventing influenza infection. Maximizing vaccination uptake rates (80-90%) is crucial in generating herd immunity and preventing infection incidence. Vaccination of healthcare professionals (HCP) against influenza is vital to infection control in healthcare settings, given their consistent exposure to high-risk patients like: those with compromised immune systems, children, and the elderly (Johnson & Talbot, 2011). Though vaccination is vital in disease prevention, influenza vaccination uptake among HCP is low overall (50% on average) (Pearson et al., 2006). Mandatory vaccination policies result in HCP influenza vaccination uptake rates substantially higher than opt-in influenza vaccination campaigns (90% vs. 60%). Therefore, influenza vaccination should be mandatory for HCP in order to best prevent influenza infection in healthcare settings. Many HCP cite individual objections to influenza vaccination rooted in personal doubts and ethical concerns, not best available scientific evidence. Nevertheless, HCP ethical responsibility to their patients and work environments to prevent and lower influenza infection incidence overrules such individual objections. Additionally, mandatory HCP influenza vaccination policies respect HCP autonomy via including medical and religious exemption clauses. While vaccination as a prevention method for influenza is logically sound, individuals’ actions are not always rooted in logic. Therefore, I analyze HCP perceptions and actions toward influenza vaccination in an effort to better explain low HCP uptake rates of the influenza vaccine and individual objections to influenza vaccination. Such analysis can aid in gaining HCP trust when implementing mandatory HCP influenza vaccination policies. In summary, mandatory HCP influenza vaccination policies are ethically justified, effective, scientifically-supported method of maximizing HCP influenza vaccine uptake and minimizing the spread of the influenza virus within healthcare settlings.
ContributorsGur-Arie, Rachel (Author) / Maienschein, Jane (Thesis advisor) / Hurlbut, Ben (Thesis advisor) / Ellison, Karin (Committee member) / Arizona State University (Publisher)
Created2016
Description
Necrotic enteritis (NE) is caused by type A strains of the bacterium Clostridium perfringens, leading to an estimated 2 billion dollar global economic loss in the poultry industry annually. Traditionally, NE has been effectively controlled by antibiotics added to the diet of poultry. Concerns about increasing antibiotic resistance of poultry and human based pathogens have led to the consideration of alternative approaches for controlling disease, such as vaccination. NE causing strains of C. perfringens produce two major toxins, α-toxin and NetB. Immune responses against either toxin can provide partial protection against NE. We have developed a fusion protein combining a non-toxic carboxy-terminal domain of the α-toxin (PlcC) and an attenuated, mutant form of NetB (NetB-W262A) for use as a vaccine antigen to immunize poultry against NE. We utilized a DNA sequence that was codon-optimized for Nicotiana benthamiana to enable high levels of expression. The 6-His tagged PlcC-NetB fusion protein was synthesized in N. benthamiana using a geminiviral replicon transient expression system. The fusion protein was purified by metal affinity chromatography and used to immunize broiler birds. Immunized birds produced a strong serum IgY response against both the plant produced PlcC-NetB protein and against bacterially produced His-PlcC and His-NetB. However, the PlcC-NetB fusion had antibody titers four times that of the bacterially produced toxoids alone. Immunized birds were significantly protected against a subsequent in-feed challenge with virulent C. perfringens when treated with the fusion protein. These results indicate that a plant-produced PlcC-NetB is a promising vaccine candidate for controlling NE in poultry.
ContributorsHunter, Joseph G (Author) / Mason, Hugh (Thesis advisor) / Mor, Tsafrir (Committee member) / Blattman, Joseph (Committee member) / Arizona State University (Publisher)
Created2018