[Quantification of feline immunodeficiency virus (FIV) RNA in the plasma of infected cats].
A competitive reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify RNA of feline immunodeficiency virus (FIV) in cats. The assay uses in vitro synthesized RNA as a competitive internal control. The synthesized RNA has a 22-base deletion with respect to the wild-type sequence. PCR products were quantitated by densitometric analysis of a digitized image of the ethidium bromide stained gel. Viral RNA concentrations in the plasma of two cats experimentally infected with FIV strain UT113 were followed for 32 weeks; peak copy numbers (2.3 x 10(4) and 1.3 x 10(4) per ml, respectively) were reached 11 weeks after subcutaneous injection of ten 50% cat infectious doses. With rising antibody titers against FIV-gag and FIV-env gene products, the amount of FIV RNA in plasma decreased. Nine asymptomatic cats that had been experimentally infected 3.5 to 4.5 years earlier had copy numbers between 5.6 x 10(3) and 4.3 x 10(4) per ml. Cats treated for six weeks with 9-(2-phosphonylmethoxy-propyl)-2,6-diaminopurine [PMPDAP] (20 mg/kg body weight s.c. three times a week) showed a significant decrease of RNA copy numbers in plasma. This quantitative competitive RT-PCR will be useful to study the pathogenesis of the FIV infection, to evaluate the effectiveness of vaccines and to monitor antiviral and immunomodulating drugs.
Vahlenkamp
T W
TW
Abteilung Virologie, Fachgruppe Infektionskrankheiten und Immunologie, Veterinärmedizinische Fakultät, Universität Utrecht Niederlande.
De Ronde
A
A
Horzinek
M C
MC
Egberink
H F
HF
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D016516:CD4-CD8 Ratio; D002415:Cats; D016181:Feline Acquired Immunodeficiency Syndrome / Q000821:virology*; D016089:Immunodeficiency Virus, Feline / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012367:RNA, Viral / Q000097:blood*; D014766:Viremia / Q000821:virology*
D000914:Antibodies, Viral; D012367:RNA, Viral