A DNA vaccine for West Nile virus (WNV) was evaluated to determine whether its use could protect fish crows (Corvus ossifragus) from fatal WNV infection. Captured adult crows were given 0.5 mg of the DNA vaccine either orally or by intramuscular (IM) inoculation; control crows were inoculated or orally exposed to a placebo. After 6 weeks, crows were challenged subcutaneously with 105 plaque-forming units of WNV (New York 1999 strain). None of the placebo inoculated–placebo challenged birds died. While none of the 9 IM vaccine–inoculated birds died, 5 of 10 placebo-inoculated and 4 of 8 orally vaccinated birds died within 15 days after challenge. Peak viremia titers in birds with fatal WNV infection were substantially higher than those in birds that survived infection. Although oral administration of a single DNA vaccine dose failed to elicit an immune response or protect crows from WNV infection, IM administration of a single dose prevented death and was associated with reduced viremia.

The New York 1999 strain of West Nile virus (WNV) is nearly 100% fatal in the American crow (Corvus brachyrhynchos). We evaluated four WNV vaccine formulations in American crows, including intramuscular (i.m.) DNA vaccine, i.m. DNA vaccine with adjuvant, orally administered microencapsulated DNA vaccine, and i.m. killed vaccine. Neutralizing antibodies developed in approximately 80% of crows that received the DNA vaccine i.m. (with or without adjuvant), and in 44% that received the killed vaccine. However, no crows that received the oral microencapsulated DNA vaccine or the placebo developed WNV antibodies. All crows were challenged 10 wk after initial vaccination. No unvaccinated crows survived challenge, and survival rates were 44% (i.m. DNA vaccine), 60% (i.m. DNA vaccine with adjuvant), 0% (oral microencapsulated DNA vaccine), and 11% (killed vaccine). Peak viremia titers in the birds that survived were significantly lower as compared to titers in birds that died. Parenteral administration of a WNV DNA vaccine was associated with reduced mortality but did not provide sterile immunity.

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To serve as model cell or tissue specific drug delivery systems spermine alginate capsules were surface modified by attachment of proteins with carbohydrate specific binding properties, i.e. lectins. In the first of a two step process avidin was covalently bound to the capsule surfaces using a hydroxy-succinimide catalysed carbodiimide reagent. Surface bound avidin was quantitated by lysing the capsules in hypertonic phosphate buffered saline (PBS) and measuring the change in absorbance at 500 nm in the interaction with 2-(4'hydroxyazobenzene) benzoic acid. A time course study of the avidin-binding reaction showed avidin surface concentrations averaged 5.4 nM/cm2 after 16h. In the second step avidin-coated capsules were incubated in aqueous solutions of biotinylated-lectin derivatives. To quantitate lectin uptake, avidin-coated capsules were lysed in PBS and titrated to the turbidance endpoint with ten different biotinylated lectins. Lectin surface concentrations ranged from 2.0 to 6.8 nm/cm2, well below the theoretical limit of 4 biotinylated ligands per molecule of avidin. Individual lectins bound to capsular surfaces retained their respective ligand specific binding properties as demonstrated by measurement of the selective saturable uptake of radiolabeled ligands when incubated with variously lectin coated capsules. The presence of porcine gastric mucin in concentrations up to 4% w/v did not inhibit binding of 14C-labelled mannose or galactose by concanavalin A-coated capsules.

; New York 1999 strain of West Nile virus (WNV) is nearly 100% fatal in the American crow (Corvus brachyrhynchos). We evaluated four WNV vaccine formulations in American crows, including intramuscular (i.m.) DNA vaccine, i.m. DNA vaccine with adjuvant, orally administered microencapsulated DNA vaccine, and i.m. killed vaccine. Neutralizing antibodies developed in approximately 80% of crows that received the DNA vaccine i.m. (with or without adjuvant), and in 44% that received the killed vaccine. However, no crows that received the oral microencapsulated DNA vaccine or the placebo developed WNV antibodies. All crows were challenged 10 wk after initial vaccination. No unvaccinated crows survived challenge, and survival rates were 44% (i.m. DNA vaccine), 60% (i.m. DNA vaccine with adjuvant), 0% (oral microencapsulated DNA vaccine), and 11% (killed vaccine). Peak viremia titers in the birds that survived were significantly lower as compared to titers in birds that died. Parenteral administration of a WNV DNA vaccine was associated with reduced mortality but did not provide sterile immunity. RESUMEN. La vacunación del cuervo Americano (Corvus brachyrhynchos) con vacuna de ADN proporciona protección parcial contra el desafío letal con el virus del Oeste del Nilo. La cepa del virus del Oeste del Nilo aislada en Nueva York en el año 1999 es casi 100% fatal en el cuervo Americano (Corvus brachyrhynchos). Evaluamos cuatro formulaciones de vacunas en cuervos Americanos, incluyendo una vacuna de ADN, una vacuna de ADN con adyuvante, ambas aplicadas por la vía intramuscular, una vacuna de ADN microencapsulada aplicada por la vía oral, y una vacuna inactivada aplicada por la vía intramuscular. Los anticuerpos neutralizantes se desarrollaron en aproximadamente el 80% de los cuervos que recibieron la vacuna de ADN por vía intramuscular, con o sin adyuvante, y en el 44% de los que recibieron la vacuna inactivada. Sin embargo, no se desarrollaron anticuerpos en los cuervos que recibieron la vacuna de ADN microencapsulada o en los controles no vacunados. Todos los cuervos fueron desafiados 10 semanas después de la vacunación inicial. Ninguno de los cuervos no vacunados sobrevivieron el desafío, y los porcentajes de sobrevivencia fueron del 44% para la vacuna de ADN, 60% para la misma vacuna con adyuvante, 0% para la vacuna de ADN microencapsulada, y 60% para la vacuna inactivada. Los títulos máximos de viremia en las aves que sobrevivieron fueron significantemente más bajos comparados con los títulos de los cuervos que murieron. La administración parenteral de la vacuna de ADN del virus del Oeste del Nilo estuvo asociada con una reducción de la mortalidad pero no proporcionó una inmunidad total. Abbreviations: ABSL-3 5 animal biosafety level-3; BA1 5 bovine albumin-1; E 5 envelope protein; i.m. 5 intramuscular; NY99 5 New York 1999 strain; PBS 5 phosphate-buffered saline; PFU 5 plaque forming units; prM 5 transmembrane protein; PRNT 5 plaque-reduction neutralization test; SLEV 5 Saint Louis encephalitis virus; WNV 5 West Nile virus