Absence of Marek's disease virus antigen in the feather follicle epithelium of vaccinated chicks demonstrated by immunofluorescence

Abstract

SUMMARYIn chickens vaccinated with MDV strain CVI 988, HVT strain FC 126 or PB-THV 1, no MDV-specific antigens could be demonstrated in the feather follicle epithelium by immunofluorescence (IF). In chickens given virulent MDV strains, the epithelium of the feather follicle was positive in IF. In an experiment where chickens were vaccinated with strain CVI 988, positive IF was observed in the lung, bursa and pancreas, but not in the feather follicle epithelium, kidney, cloaca, or caecal tonsils. Absence of IF antigen in the skin may be indicative of avirulence of the strain of MDV.

Protection of Chickens from Newcastle and Marek's Diseases with a Recombinant Herpesvirus of Turkeys Vaccine Expressing the Newcastle Disease Virus Fusion Protein

“…Third, HVT establishes a persistent viremia in chickens for many weeks following vaccination, and, therefore, the delivery of foreign antigens to the immune systems of vaccinated chickens could be expected to occur for an extended period of time. Fourth, HVT does not spread horizontally, even in high-density chicken populations (18). The environmental impact of large-scale release of such an organism in nature can be expected to be less than for organisms capable of spreading horizontally; therefore, one of the major risks associated with use of a live recombinant vector vaccine would be reduced.…”