In vitro and in vivo characterization of glycoprotein C-deleted infectious laryngotracheitis virus.
Infectious laryngotracheitis is an important respiratory disease of chickens that is caused by an alphaherpesvirus [infectious laryngotracheitis virus (ILTV); Gallid herpesvirus 1]. As herpesvirus envelope glycoproteins are main targets of the humoral host immune response, they are of particular interest for development of vaccines, as well as of diagnostic tools. The conserved, N-glycosylated envelope protein gC has been identified as a major surface antigen of ILTV. To study the function of gC, we now isolated a gC-deleted ILTV recombinant as well as a gC rescuant after co-transfection of permissive chicken cells with virion DNA and transfer plasmids containing engineered subgenomic fragments. Like other alphaherpesvirus homologues, ILTV gC proved to be non-essential for replication. ILTV-DeltagC exhibited delayed penetration kinetics and slightly reduced plaque sizes in cultured chicken cells, whereas virus titres were not reduced significantly compared with wild-type or gC-rescued virus. In vivo studies revealed that ILTV-DeltagC is attenuated in chickens. However, infection with high doses of ILTV-DeltagC was still fatal for approximately 20 % of the animals, whereas wild-type or gC-rescued ILTV led to 50 % mortality. Interestingly, innate and specific immune responses against ILTV-DeltagC were not reduced but enhanced, and surviving chickens were protected completely against challenge infection. Furthermore, ILTV-DeltagC might serve as a basis for marker vaccines permitting differentiation between vaccinated and field-virus-infected animals, as gC-specific antibodies could be detected easily in sera of animals infected with wild-type ILTV.
Pavlova
Sophia P
SP
Institute of Molecular Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
Veits
Jutta
J
Blohm
Ulrike
U
Maresch
Christina
C
Mettenleiter
Thomas C
TC
Fuchs
Walter
W
D000818:Animals; D002645:Chickens; D016679:Genome, Viral; D001352:Herpesvirus 1, Gallid / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology*; D014759:Viral Envelope Proteins / Q000276:immunology / Q000502:physiology*; D014774:Virulence; D053586:Virus Internalization; D014779:Virus Replication
D014759:Viral Envelope Proteins