Matching Items (35)
Description
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19) that emerged from a zoonotic host at the end of 2019 and caused a public health crisis. In this collection of studies, Nicotiana benthamiana plants are used to set the foundation for producing monoclonal antibodies (mAbs) with homogeneous glycosylation to neutralize SARS-CoV-2 and potentially address the immunopathology often observed with severe COVID-19. Specifically, a mAb against the human interleukin (IL)-6 receptor (sarilumab) was generated and evaluated in vitro for its potential to reduce IL-6 signaling that has been shown to be associated with more severe cases of COVID-19. Furthermore, multiple mAbs that bind to the receptor-binding domain (RBD) of SARS-CoV-2 and efficiently neutralize the virus were developed using plant-based expression. Several of these mAbs are from different classes of RBD-binding mAbs that have distinct binding sites from one another. Several mAbs from different classes showed synergy in neutralizing the ancestral strain of SARS-CoV-2 and a smaller subset showed synergy when tested against the highly mutated Omicron (B.1.1.529) variant. Of interest, a novel RBD-binding mAb, termed 11D7, that was raised against the ancestral strain and derived from a hybridoma, appears to have an epitope on the RBD that contributes more synergy to a mAb combination that efficiently neutralizes the B.1.1.529 variant of SARS-CoV-2. This epitope was partially mapped by competitive binding and shows that it overlaps with another known antibody that binds a cryptic, distal epitope, away from the receptor binding site, giving insight into the potential mechanism by which 11D7 neutralizes SARS-CoV-2, as well as potentially allowing it to resist SARS-CoV-2 immune evasion more efficiently. Furthermore, this mAb carries a highly homogeneous glycan pattern when expressed in N. benthamiana, that may contribute to enhanced effector function and provides a tool to elucidate the precise role of crystallizable fragment (Fc)-mediated protection in SARS-CoV-2 infection. Ultimately, these studies provide evidence of the utility of plant-made mAbs to be used as cocktail members, giving clarity to the use of less potent mAbs as valuable cocktail components which will spur further investigations into how mAbs with unique epitopes work together to efficiently neutralize SARS-CoV-2.
ContributorsJugler, Collin (Author) / Chen, Qiang (Thesis advisor) / Lake, Douglas (Committee member) / Steele, Kelly (Committee member) / Mason, Hugh (Committee member) / Arizona State University (Publisher)
Created2022
Description
Flaviviruses (FVs) are among the most medically important arboviruses of the world with the Dengue virus (DENV) accounting for a large percentage of infections observed in tropical and subtropical regions of the world. Globalization, travel, and the expanding range of mosquito vectors, such as Aedes aegypti, have increased the potential of infection rates and illnesses associated with FVs.
The DENV and the Zika (ZIKV) FVs frequently co-circulate and generally cause mild self-liming febrile illnesses. However, a secondary infection with a heterologous DENV serotype may lead to life threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DHF/DSS have been linked to antibody dependent enhancement of infection (ADE), a phenomenon that occurs when antibodies (Abs) formed against an initial infection with one serotype of DENV cross-reacts but does not neutralize a heterologous DENV serotype in a secondary infection. Furthermore, Abs raised against the ZIKV have been observed to cross-react with the DENV and vice versa, which can potentially cause ADE and lead to severe DENV disease. The ZIKV can be transmitted vertically and has been linked to devastating congenital defects such as microcephaly in newborns. FDA approved treatments do not exist for DENV and ZIKV illnesses. Thus, there is a need for safe and effective treatments for these co-circulating viruses. Here, a tetravalent bispecific antibody (bsAb) targeting the ZIKV and all four serotypes of the DENV was expressed in the Nicotiana benthamiana (N. benthamiana) plant. Functional assays of the DENV/ZIKV bsAb demonstrated binding, neutralization, and a significant reduction in ADE activity against both the DENV and the ZIKV.
A single chain variable fragment (scFv) and a diabody based on an antibody directed against the immune checkpoint inhibitor PD-L1, were also expressed in N. benthamiana leaves. The smaller sizes of the scFv and diabody confers them with the ability to penetrate deeper tissues making them beneficial in diagnostics, imaging, and possibly cancer therapy. The past few decades has seen long strives in recombinant protein production in plants with significant improvements in production, safety, and efficacy. These characteristics make plants an attractive platform for the production of recombinant proteins, biologics, and therapeutics.
The DENV and the Zika (ZIKV) FVs frequently co-circulate and generally cause mild self-liming febrile illnesses. However, a secondary infection with a heterologous DENV serotype may lead to life threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DHF/DSS have been linked to antibody dependent enhancement of infection (ADE), a phenomenon that occurs when antibodies (Abs) formed against an initial infection with one serotype of DENV cross-reacts but does not neutralize a heterologous DENV serotype in a secondary infection. Furthermore, Abs raised against the ZIKV have been observed to cross-react with the DENV and vice versa, which can potentially cause ADE and lead to severe DENV disease. The ZIKV can be transmitted vertically and has been linked to devastating congenital defects such as microcephaly in newborns. FDA approved treatments do not exist for DENV and ZIKV illnesses. Thus, there is a need for safe and effective treatments for these co-circulating viruses. Here, a tetravalent bispecific antibody (bsAb) targeting the ZIKV and all four serotypes of the DENV was expressed in the Nicotiana benthamiana (N. benthamiana) plant. Functional assays of the DENV/ZIKV bsAb demonstrated binding, neutralization, and a significant reduction in ADE activity against both the DENV and the ZIKV.
A single chain variable fragment (scFv) and a diabody based on an antibody directed against the immune checkpoint inhibitor PD-L1, were also expressed in N. benthamiana leaves. The smaller sizes of the scFv and diabody confers them with the ability to penetrate deeper tissues making them beneficial in diagnostics, imaging, and possibly cancer therapy. The past few decades has seen long strives in recombinant protein production in plants with significant improvements in production, safety, and efficacy. These characteristics make plants an attractive platform for the production of recombinant proteins, biologics, and therapeutics.
ContributorsEsqueda, Adrian (Author) / Chen, Qiang (Thesis advisor) / Arntzen, Charles (Committee member) / Lake, Douglas (Committee member) / Mason, Hugh (Committee member) / Arizona State University (Publisher)
Created2019
Description
Adoptive transfer of T cells engineered to express synthetic antigen-specific T cell receptors (TCRs) has provocative therapeutic applications for treating cancer. However, expressing these synthetic TCRs in a CD4+ T cell line is a challenge. The CD4+ Jurkat T cell line expresses endogenous TCRs that compete for space, accessory proteins, and proliferative signaling, and there is the potential for mixed dimer formation between the α and β chains of the endogenous receptor and that of the synthetic cancer-specific TCRs. To prevent hybridization between the receptors and to ensure the binding affinity measured with flow cytometry analysis is between the tetramer and the TCR construct, a CRISPR-Cas9 gene editing pipeline was developed. The guide RNAs (gRNAs) within the complex were designed to target the constant region of the α and β chains, as they are conserved between TCR clonotypes. To minimize further interference and confer cytotoxic capabilities, gRNAs were designed to target the CD4 coreceptor, and the CD8 coreceptor was delivered in a mammalian expression vector. Further, Golden Gate cloning methods were validated in integrating the gRNAs into a CRISPR-compatible mammalian expression vector. These constructs were transfected via electroporation into CD4+ Jurkat T cells to create a CD8+ knockout TCR Jurkat cell line for broadly applicable uses in T cell immunotherapies.
ContributorsHirneise, Gabrielle Rachel (Author) / Anderson, Karen (Thesis advisor) / Mason, Hugh (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2020
Description
Climate change has the potential to reduce the amount of land that is suitable for crop growth. Such changes may cause food shortages, which would most likely disproportionately affect the poorest regions of the world. While GMO crops showed potential to increase crop yield and agricultural efficiency, significant public pushback has led to a search for alternative methods to generate similar results. Compounds produced by bacteria, such as 2,3-butanediol, offer a potential way to change the phenotypes of plants without the deliberate genomic changes involved in the development of GMOs which are often the subject of great controversy. These compounds influence how plants grow and function. Through precise application, the compounds could be used to improve crop yield and stress tolerance. While these effects are not completely understood, they may be due to changes in transcription and translation of certain proteins, the microbiome surrounding the plants and its interactions with the compounds, or other unknown factors. The compound 2,3-butanediol appears to increase biomass, lead to larger root systems and more root hairs, and increase germination rates in a variety of plants. All these traits are favorable for producing higher yields and enduring stress conditions. The phenotypes induced by this compound are similar to plants engineered to over express a type I proton pyrophosphatase. Plants treated with 2,3-butanediol offer a potential option to achieve the benefits of GMO crops without the attached social stigma.
ContributorsOlson, Erik Jon (Co-author) / Olson, Erik (Co-author) / Gaxiola, Roberto (Thesis director) / Mason, Hugh (Committee member) / Riley, James (Committee member) / School of Life Sciences (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
Description
Electronic Health Records: Suggestions for Future Use explores how EHRs are currently being used in the clinical setting and in the research setting. This paper provides suggestions for how EHRs should be used in the future, so that patient centered health care is optimized while maintaining efficiency. Additionally, the thesis discusses why privacy is viewed as an innate human right in society as well as why it is specifically valued in the healthcare setting. The value of privacy significantly impacts how EHRs are currently used, and the more automated EHR systems become, the more likely it is that the privacy of patients is threatened. It was concluded that the healthcare industry can improve EHR use in future clinical and research settings, while upholding privacy laws.
ContributorsPhillips, Emily (Co-author) / Waldman, Lauren (Co-author) / Brian, Jennifer (Thesis director) / Mason, Hugh (Committee member) / Department of English (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Inhibitor of growth factor 4 (ING4) is a tumor suppressor of which low expression has been associated with poor patient survival and aggressive tumor progression in breast cancer. ING4 is characterized as a transcription regulator of inflammatory genes. Among the ING4-regulated genes is CXCL10, a chemokine secreted by endothelial cells during normal inflammation response, which induces chemotactic migration of immune cells to the site. High expression of CXCL10 has been implicated in aggressive breast cancer, but the mechanism is not well understood. A potential signaling molecule downstream of Cxcl10 is Janus Kinase 2 (Jak2), a kinase activated in normal immune response. Deregulation of Jak2 is associated with metastasis, immune evasion, and tumor progression in breast cancer. Thus, we hypothesized that the Ing4/Cxcl10/Jak2 axis plays a key role in breast cancer progression. We first investigated whether Cxcl10 affected breast cancer cell migration. We also investigated whether Cxcl10-mediated migration is dependent on ING4 expression levels. We utilized genetically engineered MDAmb231 breast cancer cells with a CRISPR/Cas9 ING4-knockout construct or a viral ING4 overexpression construct. We performed Western blot analysis to confirm Ing4 expression. Cell migration was assessed using Boyden Chamber assay with or without exogenous Cxcl10 treatment. The results showed that in the presence of Cxcl10, ING4-deficient cells had a two-fold increase in migration as compared to the vector controls, suggesting Ing4 inhibits Cxcl10-induced migration. These findings support our hypothesis that ING4-deficient tumor cells have increased migration when Cxcl10 signaling is present in breast cancer. These results implicate Ing4 is a key regulator of a chemokine-induced tumor migration. Our future plan includes evaluation of Jak2 as an intermediate signaling molecule in Cxcl10/Ing4 pathway. Therapeutic implications of these findings are targeting Cxcl10 and/or Jak2 may be effective in treating ING4-deficient aggressive breast cancer.
ContributorsArnold, Emily (Author) / Kim, Suwon (Thesis director) / Blattman, Joseph (Thesis director) / Mason, Hugh (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Fusion protein immunotherapies such as the bispecific T cell engager (BiTE) have displayed promising potential as cancer treatments capable of engaging the immune system against tumor cells. It has been shown that chlorotoxin, a 36-amino peptide found in the venom of the deathstalker scorpion (Leiurus quinquestriatus), binds specifically to glioblastoma (GBM) cells without binding healthy tissue, making it an ideal GBM cell binding moiety for a BiTE-like molecule. However, chlorotoxin’s four disulfide bonds pose a folding challenge outside of its natural context and impede production of the recombinant protein in various expression systems, including those relying on bacteria and plants. To overcome this difficulty, we have engineered a truncated chlorotoxin variant (Cltx∆15) that contains just two of the original eight cystine residues, thereby capable of forming only a single disulfide bond while maintaining its ability to bind GBM cells. We further created a BiTE (ACDClx∆15) which tethers Cltx∆15 to a single chain ⍺-CD3 antibody in order to bring T cells into contact with GBM cells. The gene for ACDClx∆15 was cloned into a pET-11a vector for expression in Escherichia coli and isolated from inclusion bodies before purification via affinity chromatography. Immunoblot analyses confirmed that ACDClx∆15 can be expressed in E. coli and purified with high yield and purity; moreover, flow cytometry indicated that ACDClx∆15 is capable of binding GBM cells. These data warrant further investigation into the ability of ACDClx∆15 to activate T cells against GBM cells.
ContributorsSchaefer, Braeden Scott (Author) / Mor, Tsafrir (Thesis director) / Mason, Hugh (Committee member) / Cook, Rebecca (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
HIV continues to remain a global health issue, in particular in many low and middle-income countries. The World Health Organization (WHO) estimates that of the nearly 38 million HIV-1 positive individuals, 25% are unaware they are infected. Despite decades of research, a safe and effective preventative vaccine has yet to be produced. The HIV-1 envelope glycoprotein41 and the Gag structural protein have been identified to be particularly important in HIV-1 transcytosis and cytotoxic lymphocyte response, respectively. Enveloped virus-like particles (VLPs) consisting of Gag and a deconstructed form of glycoprotein (dgp41) comprising the membrane proximal external region (MPER), transmembrane domain and cytoplasmic tail may present a unique and safe way of presenting these proteins in a state mimicking their natural formation. Another form of presenting the immunogenic glycoprotein41, particularly the MPER component, is by presenting it onto the N-terminal of an IgG molecule, thereby creating an IgG fusion molecule. In our lab, both VLPs and IgG fusion molecules are highly expressed and purified within GnGn Nicotiana benthamiana. The results indicated that these recombinant proteins can be assembled properly within plants and can elicit an immune response in mice. This provides a preliminary step in using such Gag/dpg41 VLPs and RIC as present a safe, effective, and inexpensive HIV vaccine.
ContributorsGarcia, Izamar (Author) / Mor, Tsafrir (Thesis director) / Mason, Hugh (Committee member) / Kamzina, Aigerim (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Plant-made virus-like particles (VLPs), composed of HIV-1 Gag and deconstructed gp41 proteins, have been shown to be safe and immunogenic in mice. Here, we report the successful production of HIV-1 Gag/dgp41 VLPs in Nicotiana benthamiana, using an enhanced geminivirus-based expression vector. This novel vector results in unique expression kinetics, with peak protein accumulation and minimal necrosis achieved on day 4 post-infiltration. In comparing various purification strategies, it was determined that a 20% ammonium sulfate precipitation is an effective and efficient method for removing plant proteins and purifying the recombinant VLPs of interest. If further purification is required, this may be achieved through ultracentrifugation. VLPs are a useful platform for a variety of biomedical applications and developing the technology to efficiently produce VLPs in the plant expression system is of critical importance.
ContributorsFleming, Claire (Author) / Mor, Tsafrir (Thesis director) / Mason, Hugh (Committee member) / Kamzina, Aigerim (Committee member) / Barrett, The Honors College (Contributor) / Department of Physics (Contributor) / School of Life Sciences (Contributor)
Created2022-05
Description
Influenza virus A (IVA) poses a serious threat to human health, killing over 25,000 Americans in the 2022 flu season alone. In the past 10 years, vaccine efficacy has varied significantly, ranging from 20-60% each season. Because IVA is subject to high antigenic shift and strain cocirculation, more effective IVA vaccines are needed to reduce the incidence of disease. Herein we report the production of a recombinant immune complex (RIC) vaccine “4xM2e” in Nicotiana benthamiana plants using agroinfiltration for use as a potential universal IVA vaccine candidate. RICs fuse antigen to the C-terminus of an immunoglobulin heavy chain with an epitope tag cognate to the antibody, promoting immune complex formation to increase immunogenicity. IVA matrix protein 2 ectodomain (M2e) is selected to serve as vaccine antigen for its high sequence conservation, as only a small number of minor mutations have occurred since its discovery in 1981 in the human sequence. However, there is some divergence in zoonotic IVA strains, and to account for this, we designed a combination of human consensus, swine, and avian M2e variants, 4xM2e. This was fused to the C terminus of the RIC platform to improve M2e immunogenicity and IVA strain coverage. The 4xM2e RIC was produced in N. benthamiana and verified with SDS-PAGE and Western blot assays, along with an analysis of complex formation and the potential for complement activation via complement C1q ELISA. With this work, we demonstrate the potential of RICs and plant-expression systems to generate universal IVA vaccine candidates.
ContributorsLesio, Joshua (Author) / Mason, Hugh (Thesis director) / Holechek, Susan (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Life Sciences (Contributor)
Created2023-05