Vaccination of Captive Nēnē (Branta sandvicensis) against West Nile Virus Using a Protein-based Vaccine (WN-80E)

Abstract

Although West Nile Virus (WNV) has not been reported in Hawai'i, eventual introduction appears unavoidable with potential adverse effects on avian species. Nēnē (Branta sandvicensis) are endemic endangered Hawaiian geese that are susceptible to WNV. We demonstrate that a vaccine developed against WNV for humans (WN-80E) is also highly immunogenic in Nēnē and does not produce adverse biologic effects. Six captive, nonbreeding Nēnē were immunized with two 10-μg doses (4 wk apart) of the WN-80E recombinant protein adjuvanted with Montanide ISA720. Two Nēnē were similarly injected with "mock" preparation as controls. Blood samples were collected before the first dose, then 2 wk and 6 mo after the second dose. WNV-specific antibody titers were determined by an endpoint enzyme-linked immunosorbent assay. An unpaired t-test demonstrated significantly higher geometric mean titers for immunized vs. control groups 2 wk after dose 2 (4,129 and 100, respectively, P=0.010) and 6 mo after dose 2 (246 and 63, respectively, P=0.002). Daily observations revealed no swelling at the site of injection and no serious adverse biological effects from the immunization. The vaccine containing the WN-80E and Montanide ISA720 adjuvant appears to be safe and immunogenic in Nēnē. This protein-based WNV vaccine may be safer for use in Hawai'i than killed virus and live chimeric or recombinant canarypox-vectored vaccines because it cannot cause disease.

Non-conventional expression systems for the production of vaccine proteins and immunotherapeutic molecules

“…The resultant cell line, Drosophila Schneider line 2, is today used as a stable, nonviral and nonlytic expression system able to successfully produce difficult to express proteins and suitable for cultivation using batch, fed-batch, and continuous cultivation techniques. Indeed, S2 cells have been used over the last 10 y for the clinical development of vaccines, including a subunit vaccine targeting HER2-positive breast cancer, developed by Pharmexa A/S and currently in phase II clinical trials, and vaccines against dengue virus (Merck, Inc. 86 ) and West Nile virus (Hawai Biotech 87 ) currently in phase I development. Additionally, 2 malaria vaccines, from the Jenner Institute and Copenhagen University, respectively, are soon expected to enter phase I.…”

West Nile virus from an avian conservation perspective

“…Although there are currently no vaccines licensed for use in birds, vaccination has become routine in some zoological, private and educational collections, and has served as a management strategy for threatened or endangered species (Clark et al ., ; Chang et al ., ; Boyce et al ., ; Glavis et al ., ; Wheeler et al ., ; Jarvi et al ., ). In general, vaccines licensed for use in horses, as well as numerous proprietary or experimental vaccines, have yielded inconsistent results in birds, often eliciting limited or no anti‐WNV antibody production.…”

“…Furthermore, an estimated seven to 70 WNV‐infectious mosquitoes reach Hawaii by airplane annually (Kilpatrick et al ., ). Therefore, vaccination of a group of Hawaiian geese was performed to assess its efficacy in the event that this measure becomes necessary to ensure their long‐term survival in their native habitats (Jarvi et al ., ).…”

Current Progress of Avian Vaccines Against West Nile Virus

“…Another DNA vaccine that codes for the prM/M and E proteins of WNV produced by Aldevron [99], and two DNA-plasmid vaccines expressing the ectodomain of the WNV E protein of lineage 1 or 2 in the modified backbone vector pVax1 were also tested [113]. Likewise, a recombinant protein vaccine originally developed for humans, the WN-80E, consisting of a portion of the WNV envelope protein has been assayed too [114]. All these vaccines, commercial and experimental, have been evaluated in different domestic ( Table 2) and wild (Table 1) avian species following different routes of administration and vaccination regimens, resulting in varied outcomes.…”