Reassessment of feline leukaemia virus (FeLV) vaccines with novel sensitive molecular assays.
We previously described antigen negative, provirus positive cats. Subsequently, we hypothesized that efficacious FeLV vaccines cannot prevent minimal viral replication. Thus, we vaccinated cats with either a canarypox-vectored live or a killed virus vaccine and analyzed the challenge outcome with quantitative PCR and a newly established real-time RT-PCR. When judged by conventional parameters (antigenaemia, virus isolation), most of the vaccinated cats were, as expected, protected from persistent viraemia. However, all cats were found to be plasma viral RNA positive. The loads were significantly associated with the infection outcome. Thus, commonly used FeLV vaccines understood to be successful model antiretroviral vaccines protecting against FeLV-related diseases do not confer sterilizing immunity.
Hofmann-Lehmann
Regina
R
Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, CH-8057 Zurich, Switzerland. rhofmann@vetclinics.unizh.ch
Tandon
Ravi
R
Boretti
Felicitas S
FS
Meli
Marina L
ML
Willi
Barbara
B
Cattori
Valentino
V
Gomes-Keller
Maria A
MA
Ossent
Pete
P
Golder
Matthew C
MC
Flynn
J Norman
JN
Lutz
Hans
H
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002415:Cats; D004797:Enzyme-Linked Immunosorbent Assay; D005256:Leukemia Virus, Feline / Q000276:immunology*; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014611:Vaccination; D019562:Viral Load; D014765:Viral Vaccines / Q000276:immunology*; D014766:Viremia / Q000517:prevention & control
D000914:Antibodies, Viral; D012367:RNA, Viral; D014765:Viral Vaccines