Location: Endemic Poultry Viral Diseases Research
Title: Maternally derived antibodies in commercial broiler chickens did not significantly interfere with protection of Newcastle disease virus vectored infectious laryngotracheitis vaccinesAuthor
Yu, Qingzhong | |
Spatz, Stephen | |
LI, YUFENG - Shandong Poultry Research Institute, China | |
YANG, JINLONG - Chongqing Academy Of Animal Sciences | |
ZHAO, WEI - Beijing Centers For Disease And Prevention, Department Of Pest Inspection | |
ZHANG, ZHENYU - Northwest Agricultural University | |
WEN, GUOYUAN - Hubei Academy Of Agricultural Sciences | |
GARCIA, MARICARMEN - University Of Georgia | |
Zsak, Laszlo |
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 2/23/2018 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Newcastle disease virus (NDV) recombinants expressing the infectious laryngotracheitis virus (ILTV) glycoproteins B and D have previously been demonstrated to confer complete clinical protection against virulent ILTV and NDV challenges in naive chickens. However, there was a general concern that the maternally derived antibodies (MDA) in chicks may interfere with the immunoresponses to the corresponding vaccines. In this study, we assessed whether MDA against NDV and ILTV would interfere with protection in vaccinated broiler chickens. Chickens with a mean NDV MDA hemagglutination inhibition (HI) titer of 6.4 (log2) and detectable ILTV neutralization (VN) antibodies at hatch were vaccinated with rLS/ILTV-gB or rLS/ILTV-gD at 1 or 10 day of age (DOA) or on both days. Groups of birds vaccinated with the commercial ILT vaccines (FP-LT and CEO) or sham inoculated were also included as controls. All vaccinated birds were challenged with virulent ILTV strain at 21 DOA. By that time, NDV HI titers declined to 2.6 (log2) in unvaccinated birds, whereas the HI titers in NDV vectored vaccine groups increased to 3.5-6.3 (log2). At standard dosages, both vaccine candidates conferred significant clinical protection; however, the protection elicited by the rLS/ILTV-gD was superior to that of rLS/ILTV-gB. Recombinant rLS/ILTV-gD reduced ILTV shedding from tracheal and ocular tissues by approximately 3 log10 TCID50. Overall results indicate that the presence of maternal antibodies to NDV and ILTV did not significantly interfere with the ability of the NDV LaSota strain-vectored ILTV gB and gD vaccine candidates to elicit protective immunity against infectious laryngotracheitis. |