Immunogenicity of a West Nile Virus DIII-Cholera Toxin A₂/B Chimera After Intranasal Delivery

Authors

Juliette K. Tinker, Boise State UniversityFollow
Jie Yan, Boise State UniversityFollow
Reece J. Knippel, Boise State UniversityFollow
Panos Panayiotou, Boise State University
Kenneth A. Cornell, Boise State UniversityFollow

Document Type

Article

Publication Date

4-22-2014

DOI

http://dx.doi.org/10.3390/toxins6041397

Abstract

West Nile virus (WNV) causes potentially fatal neuroinvasive disease and persists at endemic levels in many parts of the world. Despite advances in our understanding of WNV pathogenesis, there remains a significant need for a human vaccine. The domain III (DIII) region of the WNV envelope protein contains epitopes that are the target of neutralizing antibodies. We have constructed a chimeric fusion of the non-toxic cholera toxin (CT) CTA₂/B domains to DIII for investigation as a novel mucosally-delivered WNV vaccine. Purification and assembly of the chimera, as well as receptor-binding and antigen delivery, were verified by western blot, GM1 ELISA and confocal microscopy. Groups of BALB/c mice were immunized intranasally with DIII-CTA₂/B, DIII, DIII mixed with CTA₂/B, or CTA₂/B control, and boosted at 10 days. Analysis of serum IgG after 14 and 45 days revealed that mucosal immunization with DIII-CTA₂/B induced significant DIII-specific humoral immunity and drove isotype switching to IgG2a. The DIII-CTA₂/B chimera also induced antigen-specific IgM and IgA responses. Bactericidal assays indicate that the DIII-CTA₂/B immunized mice produced DIII-specific antibodies that can trigger complement-mediated killing. A dose escalation resulted in increased DIII-specific serum IgG titers on day 45. DIII antigen alone, in the absence of adjuvant, also induced significant systemic responses after intranasal delivery. Our results indicate that the DIII-CTA₂/B chimera is immunogenic after intranasal delivery and merits further investigation as a novel WNV vaccine candidate.

Copyright Statement

This document was originally published by Multidisciplinary Digital Publishing Institute (MDPI) in Toxins. This work is provided under a Creative Commons Attribution 3.0 License. Details regarding the use of this work can be found at: http://creativecommons.org/licenses/by/3.0/. doi: 10.3390/toxins6041397

Publication Information

Tinker, Juliette K.; Yan, Jie; Knippel, Reece J.; Panayiotou, Panos; and Cornell, Kenneth A.. (2014). "Immunogenicity of a West Nile Virus DIII-Cholera Toxin A₂/B Chimera After Intranasal Delivery". Toxins, 6(4), 1397-1418.