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Academy of Military Medical Science

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1 Academy of Military Medical Science
Vaccination of dogs using a recombinant canine adenovirus type-2 viral vector confers long-lasting immunity against rabies Veterinary Institute Academy of Military Medical Science Changchun, Jilin, China 28 May, 2007 Paris

2 Human rabies in China in the most recent decade
159 222 229 343 495 891 1191 2037 2651 2548 3215 500 1000 1500 2000 2500 3000 3500 1996 1997 1998 1999 2002 2003 2004 2005 2006 2001 Year Human rabies in China in the most recent decade Human rabies cases geological distribution in China

3 Rabies reservoir or vectors in China
Dogs: 98% Cats: 4-5% Badger: 15 cases were reported Rats: in some areas in the south of China Foxes: Inner Mongolia Wolves: Xinjiang Bats:?

4 Vaccines for dogs in China
ERA: in five combined vaccines Flury LEP: approved for two years Inactivated (imported) : Intervet, Merial, Fort Dodge Inactivated (home-made): 3-4 types, in clinical trial, not yet approved * Vaccination of inactivated vaccine in rural areas needs laborious work.

5 Oral vaccines for dogs Attenuated or mutated live rabies virus SAD-B19
SAG1 SAG2 reverse genetically modified …… Recombinant live virus vector Poxvirus-vector based Adenovirus-vector based

6 Advantages of adenovirus
Safe Wide range of host Heat stable (Oral infection) Median package of a foreign gene Persistent existence ?

7 Adenovirus Hu RL et al. Microbes Infect, 2006, 8(4): 1090-1097
Liu Y, Hu R, Zhang S, et al Viral Immunology, 2006(19), 2: Patent1: Patent2: Non-essential for replication Foreign gene or label inserts Fiber pIX

8 Strategies for recombinant virus construction
Homologous recombination Gene cloning

9 Our constructs Glycoprotein: SRV9 CVS-24 8202(street strain)
Nucleoprotein: The recombinant CAV-2 genome containing the rabies virus glycoprotein expression cassette in plasmid form

10 Production of the recombinant virus
MDCK cells CPE Western blot analysis Handling of canine adenovirus (safe) MDCK easy grown Obvious CPE High titer: around 10(8.5)

11 Bait composition Five parts: the recombinant virus solution;
pledget; tallow; metal frame; paper package

12 Bait uptake

13 Vaccination and antibody induction in dogs
Inoculation routes Total No. dogs Take the baits or vaccinated Develop neutralizing antibody Antibody last for 2 years at a protective level Bait (oral) 96 90/96 79/90 (87.8%) 72/90(80.0%) Solution (intranasal) 46 46/46 40/46 (87.0%) 36/46(78.3%)

14 Antibody production and persistence

15 Challenge results of dogs orally vaccinated and the negative controls
Groups Number of dogs died after different time of vaccination Dogs survived 1 week 2 weeks 3 weeks 4 weeks 5 weeks Orally vaccinated 10 Negative control 6 3 1

16 Prospect In cats In pigs In cattle and more Dogs Bats

17 Conclusions A new, safe and efficacious rabies vaccine
A simple and useful bait For oral use Long lasting immunization in dogs


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