Matching Items (5)
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- All Subjects: Measles
- All Subjects: Antibodies
- Creators: Reyes del Valle, Jorge
Description
Background: Measles virus (MV) infections are the main cause of vaccine-preventable death in children younger than 5 years. The World Health Organization (WHO) has estimated there are over 20 million cases of measles every year. Currently, diagnostic methods rely on enzyme immunoassays (EIA) to detect IgM or IgG Abs in serum. These commercial assays measure reactivity against the immunodominant N antigen and can have a false negative rates of 20-30%. Centralized testing by clinical labs can delay rapid screening in an outbreak setting. This study aims to develop a rapid molecular diagnostic assay to detect IgG reactive to five individual MV proteins representing 85% of the measles proteome. Methods: MV genes were subcloned into pANT_cGST vector to generate C-terminal GST fusion proteins. Single MV cistrons were expressed using in vitro transcription/translation (IVTT) with human cell lysate. Expression of GST-tagged proteins was measured using a sandwich ELISA for GST expression using relative light units (RLUs) as readouts. Single MV antigens were used as bait to determine the IgG-dependent reactivity in 12 serum samples obtained from immunized animals with previously determined neutralization titer (NT) and the correlation between NT and ELISA reactivity was determined. Results: Protein expression of five measles genes of interest, M, N, F, H, and L, was measured. L exhibited the strongest protein expression with an average RLU value of 4.34 x 10^9. All proteins were expressed at least 50% greater than control (2.33 x 10^7 RLU). As expected, reactivity against the N was the highest, followed by reactivity against M, F, H and L. The best correlation with NT titer was reactivity against F (R^2 = 0.62). Conclusion: These data indicate that the expression of single MV genes M, N, F, H, and L are suitable antigens for serologic capture analysis of measles immunity.
ContributorsMushtaq, Zuena (Author) / Anderson, Karen (Thesis director) / Reyes del Valle, Jorge (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2015-05
Description
This project aims to address the current protocol regarding the diagnosis and treatment of traumatic brain injury (TBI) in medical industries around the world. Although there are various methods used to qualitatively determine if TBI has occurred to a patient, this study attempts to aid in the creation of a system for quantitative measurement of TBI and its relative magnitude. Through a method of artificial evolution/selection called phage display, an antibody that binds highly specifically to a post-TBI upregulated brain chondroitin sulfate proteoglycan called neurocan has been identified. As TG1 Escheria Coli bacteria were infected with KM13 helper phage and M13 filamentous phage in conjunction, monovalent display of antibody fragments (ScFv) was performed. The ScFv bind directly to the neurocan and from screening, phage that produced ScFv's with higher affinity and specificity to neurocan were separated and purified. Future research aims to improve the ScFv characteristics through increased screening toward neurocan. The identification of a highly specific antibody could lead to improved targeting of neurocan post-TBI in-vivo, aiding researchers in quantitatively defining TBI by visualizing its magnitude.
ContributorsSeelig, Timothy Scott (Author) / Stabenfeldt, Sarah (Thesis director) / Ankeny, Casey (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
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
Despite the safe and effective use of attenuated vaccines for over fifty years, measles virus (MV) remains an insidious threat to global health. Problematically, infants less than one year of age, who are the most prone to severe infection and death by measles, cannot be immunized using current MV vaccines. For this dissertation, I generated and performed preclinical evaluation of two novel MV vaccine candidates. Based on data from clinical trials that showed increasing the dosage of current MV vaccines improved antibody responses in six-month-old recipients, I hypothesized that increasing the relevant antigenic stimulus of a standard titer dose would allow safe and effective immunization at a younger age. I generated two modified MVs with increased expression of the hemagglutinin (H) protein, the most important viral antigen for inducing protective neutralizing immunity, in the background of a current vaccine-equivalent. One virus, MVvac2-H2, expressed higher levels of full-length H, resulting in a three-fold increase in H incorporation into virions, while the second, MVvac2-Hsol, expressed and secreted truncated, soluble H protein to its extracellular environment. The alteration to the virion envelope of MVvac2-H2 conferred upon that virus a measurable resistance to in vitro neutralization. In initial screening in adult mouse models of vaccination, both modified MVs proved more immunogenic than their parental strain in outbred mice, while MVvac2-H2 additionally proved more immunogenic in the gold standard MV-susceptible mouse model. Remarkably, MVvac2-H2 better induced protective immunity in the presence of low levels of artificially introduced passive immunity that mimic the passive maternal immunity that currently limits vaccination of young infants, and that strongly inhibited responses to the current vaccine-equivalent. Finally, I developed a more physiological infant-like mouse model for MV vaccine testing, in which MV-susceptible dams vaccinated with the current vaccine-equivalent transfer passive immunity to their pups. This model will allow additional preclinical evaluation of the performance of MVvac2-H2 in pups of immune dams. Altogether, in this dissertation I identify a promising candidate, MVvac2-H2, for a next generation measles vaccine.
ContributorsJulik, Emily (Author) / Reyes del Valle, Jorge (Thesis advisor) / Chang, Yung (Committee member) / Blattman, Joseph (Committee member) / Hogue, Brenda (Committee member) / Nickerson, Cheryl (Committee member) / Arizona State University (Publisher)
Created2016
Description
Measles is a contagious, vaccine-preventable disease that continues to be the leading
cause of death in children younger than the age of 5 years. While the introduction of the Measles, Mumps, and Rubella vaccine (MMR) has significantly decreased morbidity and mortality rates worldwide, vaccine coverage is highly variable across global regions. Current diagnostic methods rely on enzyme immunoassays (EIA) to detect IgM or IgG Abs in serum. Commercially available Diamedix Immunosimplicity® Measles IgG test kit has been shown to have 91.1% sensitivity and 93.8% specificity, with a positive predictive value of 88.7% and a negative predictive value of 90.9% on the basis of a PRN titer of 120. There is an increasing need for rapid screening for measles specific immunity in outbreak settings. This study aims to develop a rapid molecular diagnostic assay to detect IgG reactive to three individual measles virus (MeV) proteins.
Measles virus (MeV) genes were subcloned into the pJFT7_nGST vector to generate N- terminal GST fusion proteins. Single MeV cistrons were expressed using in vitro transcription/translation (IVTT) with human cell lysate. Expression of GST-tagged proteins was measured with mouse anti-GST mAb and sheep anti-mouse IgG. Relative light units (RLUs) as luminescence was measured. Antibodies to MeV antigens were measured in 40 serum samples from healthy subjects.
Protein expression of three MeV genes of interest was measured in comparison with vector control and statistical significance was determined using the Student’s t-test (p<0.05). N expressed at the highest level with an average RLU value of 3.01 x 109 (p<0.001) and all proteins were expressed at least 50% greater than vector control (4.56 x 106 RLU). 36/40 serum samples had IgG to N (Ag:GST ratio>1.21), F (Ag:GST ratio>1.92), or H (Ag:GST ratio> 1.23).
These data indicate that the in vitro expression of MeV antigens, N, F, and H, were markedly improved by subcloning into pJFT7_nGST vector to generate N-terminal GST fusion proteins. The expression of single MeV genes N, F and H, are suitable antigens for serologic capture analysis of measles-specific antibodies. These preliminary data can be used to design a more intensive study to explore the possibilities of using these MeV antigens as a diagnostic marker.
cause of death in children younger than the age of 5 years. While the introduction of the Measles, Mumps, and Rubella vaccine (MMR) has significantly decreased morbidity and mortality rates worldwide, vaccine coverage is highly variable across global regions. Current diagnostic methods rely on enzyme immunoassays (EIA) to detect IgM or IgG Abs in serum. Commercially available Diamedix Immunosimplicity® Measles IgG test kit has been shown to have 91.1% sensitivity and 93.8% specificity, with a positive predictive value of 88.7% and a negative predictive value of 90.9% on the basis of a PRN titer of 120. There is an increasing need for rapid screening for measles specific immunity in outbreak settings. This study aims to develop a rapid molecular diagnostic assay to detect IgG reactive to three individual measles virus (MeV) proteins.
Measles virus (MeV) genes were subcloned into the pJFT7_nGST vector to generate N- terminal GST fusion proteins. Single MeV cistrons were expressed using in vitro transcription/translation (IVTT) with human cell lysate. Expression of GST-tagged proteins was measured with mouse anti-GST mAb and sheep anti-mouse IgG. Relative light units (RLUs) as luminescence was measured. Antibodies to MeV antigens were measured in 40 serum samples from healthy subjects.
Protein expression of three MeV genes of interest was measured in comparison with vector control and statistical significance was determined using the Student’s t-test (p<0.05). N expressed at the highest level with an average RLU value of 3.01 x 109 (p<0.001) and all proteins were expressed at least 50% greater than vector control (4.56 x 106 RLU). 36/40 serum samples had IgG to N (Ag:GST ratio>1.21), F (Ag:GST ratio>1.92), or H (Ag:GST ratio> 1.23).
These data indicate that the in vitro expression of MeV antigens, N, F, and H, were markedly improved by subcloning into pJFT7_nGST vector to generate N-terminal GST fusion proteins. The expression of single MeV genes N, F and H, are suitable antigens for serologic capture analysis of measles-specific antibodies. These preliminary data can be used to design a more intensive study to explore the possibilities of using these MeV antigens as a diagnostic marker.
ContributorsMushtaq, Zuena (Author) / Anderson, Karen (Thesis advisor) / Blattman, Joseph (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2016