Viral vector vaccines using fowl poxvirus (FPV) and herpesvirus of turkey (HVT) as vectors and carrying infectious laryngotracheitis virus (ILTV) genes (Vagnozzi et al., 2012).
f. Immunization Route
Intramuscular injection (i.m.)
g.
Chicken Response
Vaccination Protocol:
Live-attenuated ILT vaccines were administered as a full dose, and the recombinant vectored vaccines were administered as a half dose to mimic broiler industry practices. The viral vector vaccines were administered in ovo and subcutaneously at hatch while the live-attenuated vaccines, CEO and TCO, were administered via eye drop at 14 days of age (Vagnozzi et al., 2012).
Vaccine Immune Response Type:
VO_0003057
Challenge Protocol:
All chickens were weighed before challenge. With the exception of the NVx-NCh group, all chickens were challenged at 35 days of age with the virulent ILTV field isolate 63140 administered in a total volume of 200 µl, 100 µl intratracheally and 50 µl via eye drop per eye (Vagnozzi et al., 2012).
Efficacy:
The FPV-LT vaccine mitigated clinical signs more effectively when administered subcutaneously than in ovo (Vagnozzi et al., 2012).
Turkey herpesvirus vector laryngotracheitis vaccine (HVT/LT) expressing the glycoprotein B gene of laryngotracheitis virus (LTV) (Esaki et al., 2013).
f. Immunization Route
Intramuscular injection (i.m.)
g.
Chicken Response
Vaccination Protocol:
The chickens were vaccinated with HVT/LT by the subcutaneous route at 1 day of age (Esaki et al., 2013).
Vaccine Immune Response Type:
VO_0000287
Challenge Protocol:
The vaccinated chickens were challenged with virulent LTV at 7 weeks of age (Esaki et al., 2013).
Efficacy:
The majority of the vaccinated chickens (92%-100%) were protected against challenge with virulent LTV. Efficacy of HVT/LT was further evaluated in broiler chickens from a commercial source after in ovo vaccination to embryos at 18 days of incubation. After challenge with virulent LTV at 21 and 35 days of age, 67% and 87% of HVT/LT-vaccinated chickens did not develop LT clinical signs, respectively, while 100% (21 days of age) and 73% (35 days of age) of the challenge control chickens showed clinical signs of LT (Esaki et al., 2013).
Viral vector vaccines using fowl poxvirus (FPV) and herpesvirus of turkey (HVT) as vectors and carrying infectious laryngotracheitis virus (ILTV) genes (Vagnozzi et al., 2012).
f. Immunization Route
Intramuscular injection (i.m.)
g.
Chicken Response
Vaccination Protocol:
Live-attenuated ILT vaccines were administered as a full dose, and the recombinant vectored vaccines were administered as a half dose to mimic broiler industry practices. The viral vector vaccines were administered in ovo and subcutaneously at hatch while the live-attenuated vaccines, CEO and TCO, were administered via eye drop at 14 days of age (Vagnozzi et al., 2012).
Vaccine Immune Response Type:
VO_0000287
Challenge Protocol:
All chickens were weighed before challenge. With the exception of the NVx-NCh group, all chickens were challenged at 35 days of age with the virulent ILTV field isolate 63140 administered in a total volume of 200 µl, 100 µl intratracheally and 50 µl via eye drop per eye (Vagnozzi et al., 2012).
Efficacy:
The chicken embryo origin vaccine provided optimal protection by significantly mitigating the disease and reducing the challenge virus in chickens vaccinated via eye drop. The viral vector vaccines, applied in ovo and subcutaneously, provided partial protection, reducing to some degree clinical signs, and challenge VIRUS replication in the trachea (Vagnozzi et al., 2012).
The vaccine was titrated in a secondary chicken embryo fibroblast (CEF) monolayer in 60 mm plates. Ten-fold dilutions of the reconstituted vaccine were produced in Dulbecco’s modified Eagle medium (DMEM), and 200 μL of each dilution was added to three plate replicates. The inoculated cells were incubated at 37 °C and 5% CO2 for 5 days. At day 5 following inoculation, plaques were microscopically counted. Virus titer was calculated and recorded as 6360 plaque forming units (PFU)/per dose. (Loncoman et al., 2018)
h. Immunization Route
Intramuscular injection (i.m.)
i. Description
Innovax-ILT is a recombinant vector vaccine which uses herpesvirus of turkeys as a vector (Loncoman et al., 2018)
Efficacy:
Both recombinant-vectored ILTV vaccines provided partial protection, thereby mitigating the disease, but did not reduce challenge virus loads in the trachea (Johnson et al., 2010).
Efficacy:
rNDV gD showed complete protection against virulent ILTV challenge (Kanabagatte et al., 2014).
IV. References
1. Esaki et al., 2013: Esaki M, Noland L, Eddins T, Godoy A, Saeki S, Saitoh S, Yasuda A, Dorsey KM. Safety and efficacy of a turkey herpesvirus vector laryngotracheitis vaccine for chickens. Avian diseases. 2013; 57(2); 192-198. [PubMed: 24689173].
2. Johnson et al., 2010: Johnson DI, Vagnozzi A, Dorea F, Riblet SM, Mundt A, Zavala G, García M. Protection against infectious laryngotracheitis by in ovo vaccination with commercially available viral vector recombinant vaccines. Avian diseases. 2010; 54(4); 1251-1259. [PubMed: 21313847].
3. Kanabagatte et al., 2014: Kanabagatte Basavarajappa M, Kumar S, Khattar SK, Gebreluul GT, Paldurai A, Samal SK. A recombinant Newcastle disease virus (NDV) expressing infectious laryngotracheitis virus (ILTV) surface glycoprotein D protects against highly virulent ILTV and NDV challenges in chickens. Vaccine. 2014; 32(28); 3555-3563. [PubMed: 24793943].
4. Vagnozzi et al., 2012: Vagnozzi A, Zavala G, Riblet SM, Mundt A, García M. Protection induced by commercially available live-attenuated and recombinant viral vector vaccines against infectious laryngotracheitis virus in broiler chickens. Avian pathology : journal of the W.V.P.A. 2012; 41(1); 21-31. [PubMed: 22845318].
5. Zhao et al., 2014: Zhao W, Spatz S, Zhang Z, Wen G, Garcia M, Zsak L, Yu Q. Newcastle disease virus (NDV) recombinants expressing infectious laryngotracheitis virus (ILTV) glycoproteins gB and gD protect chickens against ILTV and NDV challenges. Journal of virology. 2014; 88(15); 8397-8406. [PubMed: 24829337].
