West Nile Virus (WNV) causes infection in the central nervous system (CNS) in several vertebrate animal species. Humans infected with WNV can develop meningitis and encephalitis, and the elderly and immunocompromised are at greatest risk for severe neurological disease and death. New threats of WNV globally and the lack of available treatments warrant studies to develop effective therapeutics and production technologies that can rapidly transfer candidate therapies into the clinical care setting in a cost conscious manner. We recently developed a plant-derived humanized MAb with promising therapeutic potential, with a desired human N-linked glycosylation pattern. This MAb (hE16) binds to a highly conserved epitope on the envelope protein of virtually all isolates worldwide and shows promising post-exposure therapeutic activity. Nonetheless, our studies show that peripheral delivery of hE16 has a limited window of efficacy in rodents: administration of a single dose of hE16 through an intravenous or intraperitoneal route at day 5 post infection or earlier improves survival rates. In comparison, delivery of hE16 directly into the brain at day 6 after infection improved protection against lethal WNV infection in hamsters. Our preliminary data show that a genetically engineered bifunctional MAb variant of hE16 (TfR-Bif) with the potential for enhanced crossing of the blood-brain barrier (BBB) can be expressed in CHO cells or plants. TfR-Bif retains its ability to bind and neutralize WNV, but importantly gains the ability to bind transferrin receptor (TfR) and endocytose into mouse brain endothelial cells. In the R21 phase of this grant, we will use the mouse TfR-specific TfR-Bif as a proof-of-principle in a mouse model of WNV infection. We will test the hypothesis that TfR-Bif can achieve higher levels in the CNS and extends the window of treatment against WNV encephalitis. To address critical safety issues in the brain, we will also identify TfR-Bif glycoforms that offer full bifunctionality with limited or specific Fc receptor (Fc?R) or C1q binding to eliminate potential antibody-dependent enhancement (ADE) of virus infection or pathogenic inflammation. In the R33 phase, we will develop an analogous bifunctional MAb with human therapeutic potential and test if plants provide distinctive advantages in safety, production cost, and scalability for large-scale production under cGMP. In addition to generating novel therapeutic reagents for WNV, this collaborative study will provides a platform for delivery of MAbs to the CNS, which should be applicable to the treatment of other infectious, inflammatory, or neoplastic diseases in the CNS.

Public Health Relevance

This study will generate novel therapeutic reagents for West Nile virus, provide a technology for delivery of therapeutics to the brain, and develop a cost-effective and scalable production technology using plants for protein therapeutics. Such technologies can be applied in the future to combat emerging infectious or non- infectious diseases or bioterrorist threats.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI101329-01
Application #
8366722
Study Section
Special Emphasis Panel (ZAI1-LG-M (M1))
Program Officer
Repik, Patricia M
Project Start
2012-06-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2013-05-31
Support Year
1
Fiscal Year
2012
Total Cost
$204,188
Indirect Cost
$48,944
Name
Arizona State University-Tempe Campus
Department
Other Health Professions
Type
Organized Research Units
DUNS #
943360412
City
Tempe
State
AZ
Country
United States
Zip Code
85287
He, Junyun; Lai, Huafang; Engle, Michael et al. (2014) Generation and analysis of novel plant-derived antibody-based therapeutic molecules against West Nile virus. PLoS One 9:e93541
He, Junyun; Peng, Li; Lai, Huafang et al. (2014) A plant-produced antigen elicits potent immune responses against West Nile virus in mice. Biomed Res Int 2014:952865
Lai, Huafang; He, Junyun; Hurtado, Jonathan et al. (2014) Structural and functional characterization of an anti-West Nile virus monoclonal antibody and its single-chain variant produced in glycoengineered plants. Plant Biotechnol J 12:1098-107
Chen, Qiang; Lai, Huafang (2013) Plant-derived virus-like particles as vaccines. Hum Vaccin Immunother 9:26-49
Leuzinger, Kahlin; Dent, Matthew; Hurtado, Jonathan et al. (2013) Efficient agroinfiltration of plants for high-level transient expression of recombinant proteins. J Vis Exp :