title: Quantification of rHVT-F genome load in feather follicles by specific real-time qPCR as an indicator of NDV-specific humoral immunity induced by day-old vaccination in SPF chickens.
abstract: The purpose of this study was to look for a reliable molecular method for confirmation of uptake of recombinant turkey herpesvirus vaccine against Newcastle disease (rHVT-F) and for use as a valuable prediction tool of Newcastle disease virus (NDV)-specific immune response in chickens deprived of maternally derived antibody (MDA). A quantitative real-time polymerase chain reaction (real-time qPCR) specific to rHVT-F was developed. The method was applied to various tissue samples taken from specific pathogen free (SPF) chickens experimentally inoculated at day-old with one dose of rHVT-F vaccine over a 6-week period. Among the tested tissues, the rHVT-F vaccine was detected predominantly in the bursa of Fabricius (BF) and the lung for the first week, followed by a progressive decline from 9 days onwards. Then, an increase of genome load was observed in the feather follicles (FF) with a peak at 2 weeks, rising to a level almost 10(3)-fold greater than in the other tissues. Importantly, the rHVT-F genome load in FF appeared to be strongly correlated to the humoral immunity specific to NDV as evaluated by haemagglutination inhibition (HI) test and NDV-specific IgG, IgM and IgA ELISAs. This is the first report of quantification of rHVT-F vaccine in FF and its correlation with the induction of ND-specific immune response in chickens with no MDA. Our data indicate that the application of this real-time qPCR assay on FF samples taken from chickens in the field may be used to confirm rHVT-F vaccine administration and uptake with the important added benefit of offering a non-disruptive sampling procedure.
authors: a Veterinary and Agrochemical Research Centre (VAR) , Ukkel , Belgium.
authors: F
authors: F
authors: Rauw
authors: S
authors: S
authors: Van Borm
authors: S
authors: S
authors: Welby
authors: E
authors: E
authors: Ngabirano
authors: Y
authors: Y
authors: Gardin
authors: V
authors: V
authors: Palya
authors: B
authors: B
authors: Lambrecht
mesh_terms: D000818:Animals; D002060:Bursa of Fabricius / Q000276:immunology; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay; D005241:Feathers / Q000276:immunology* / Q000821:virology; D005453:Fluorescence; D040741:Genetic Load; D022283:Herpesvirus Vaccines / Q000235:genetics / Q000276:immunology*; D056724:Immunity, Humoral / Q000276:immunology*; D008168:Lung / Q000276:immunology; D008957:Models, Genetic; D009521:Newcastle Disease / Q000276:immunology / Q000517:prevention & control*; D009841:Oligonucleotides / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms / Q000276:immunology*; D014421:Turkey; D014611:Vaccination / Q000379:methods / Q000662:veterinary*
chemical_list: D022283:Herpesvirus Vaccines; D009841:Oligonucleotides