title: In vitro and in vivo relevance of infectious laryngotracheitis virus gJ proteins that are expressed from spliced and nonspliced mRNAs.
abstract: The positional homologue in the infectious laryngotracheitis virus (ILTV) genome of the glycoprotein gJ gene of herpes simplex virus and the gp2 gene of equine herpesvirus 1 is expressed into four proteins of 85, 115, 160, and 200 kDa (J. Veits, B. Kollner, J. P. Teifke, H. Granzow, T. C. Mettenleiter, and W. Fuchs, Avian Dis. 47:330-342, 2003). RNA analyses revealed that these proteins are expressed from two different late (gamma2) transcripts, an unspliced 5.5-kb and a spliced 4.3-kb mRNA that are translated into proteins of 985 and 611 amino acids, respectively. ILTV gJ is incorporated into virions and is modified by N- and O-linked glycosylation. After cotransfection of chicken cells with genomic DNA of a pathogenic ILTV strain and transfer plasmids, gJ-negative ILTV mutants could be isolated. In vitro growth studies demonstrated that deletion of the gJ gene has only minor effects on direct cell-to-cell spread as measured by plaque size. However, progeny virus titers of ILTV-DeltagJ were significantly reduced in comparison to those of the parental virus and a gJ rescue mutant. After experimental infection of chickens the gJ rescue mutant, like wild-type ILTV, caused severe disease and considerable mortality, whereas ILTV-DeltagJ was significantly attenuated. All immunized animals were protected against subsequent challenge infection with virulent ILTV. In sera collected after immunization with the gJ-rescue mutant or with wild-type ILTV, gJ-specific antibodies were detectable by immunofluorescence on cells that had been transfected with a gJ expression plasmid. As expected, no gJ-specific antibodies were found in sera obtained from chickens immunized with ILTV-DeltagJ. Thus, gJ deletion mutants of ILTV might be usable as attenuated live-virus vaccines. Furthermore, the gJ gene might constitute a reliable marker for serological discrimination between vaccinated and field virus-infected chickens.
authors.affiliation: Institute of Molecular Biology, Friedrich-Loeffler-Institut, Boddenblick 5A, 17493 Greifswald-Insel Riems, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Fuchs
authors.forename: Dorothee
authors.initials: D
authors.lastname: Wiesner
authors.forename: Jutta
authors.initials: J
authors.lastname: Veits
authors.forename: Jens P
authors.initials: JP
authors.lastname: Teifke
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Mettenleiter
mesh_terms: D000818:Animals; D002645:Chickens; D006031:Glycosylation; D025921:Iltovirus / Q000737:chemistry*; D012326:RNA Splicing; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014774:Virulence
chemical_list: D014764:Viral Proteins