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- All Subjects: Plant sciences
- Creators: Chen, Qiang
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
Influenza is a deadly disease that poses a major threat to global health. The surface proteins of influenza A, the type most often associated with epidemics and pandemics, mutate at a very high frequency from season to season, reducing the efficacy of seasonal influenza vaccines. However, certain regions of these proteins are conserved between strains of influenza A, making them attractive targets for the development of a ‘universal’ influenza vaccine. One of these highly conserved regions is the ectodomain of the influenza matrix 2 protein (M2e). Studies have shown that M2e is poorly immunogenic on its own, but when properly adjuvanted it can be used to induce protective immune responses against many strains of influenza A. In this thesis, M2e was fused to a pair experimental ‘vaccine platforms’: an antibody fusion protein designed to assemble into a recombinant immune complex (RIC) and the hepatitis B core antigen (HBc) that can assemble into virus-like particles (VLP). The two antigens were produced in Nicotiana benthamiana plants through the use of geminiviral vectors and were subsequently evaluated in mouse trials. Mice were administered three doses of either the VLP alone or a 1:1 combination of the VLP and the RIC, and recipients of both the VLP and RIC exhibited endpoint anti-M2e antibody titers that were 2 to 3 times higher than mice that received the VLP alone. While IgG2a:IgG1 ratios, which can suggest the type of immune response (TH1 vs TH2) an antigen will elicit, were higher in mice vaccinated solely with the VLP, the higher overall titers are encouraging and demonstrate a degree of interaction between the RIC and VLP vaccines. Further research is necessary to determine the optimal balance of VLP and RIC to maximize IgG2a:IGg1 ratios as well as whether such interaction would be observed through the use of a variety of diverse antigens, though the results of other studies conducted in this lab suggests that this is indeed the case. The results of this study demonstrate not only the successful development of a promising new universal influenza A vaccine, but also that co-delivering different types of recombinant vaccines could reduce the total number of vaccine doses needed to achieve a protective immune response.
ContributorsFavre, Brandon Chetan (Author) / Mason, Hugh S (Thesis advisor) / Mor, Tsafrir (Committee member) / Chen, Qiang (Committee member) / Arizona State University (Publisher)
Created2019