Infection of cats by injection with DNA of a feline immunodeficiency virus molecular clone

Establishment of infection of animals with a viral clone will be important for investigating viral determinants of pathogenesis and monitoring sequence changes in the viral genome in vivo and may find utility as a means of immunization with live-attenuated virus. To test the efficiency of intramuscular (im) injection of cloned proviral plasmid DNA for establishing feline immunodeficiency virus (FIV) infection in specific pathogen-free (SPF) cats, groups of cats were inoculated by the im route with 300, 100, or 30 mu g of plasmid DNA containing the infectious molecular clone, FIV-pPPR. A fourth group of cats was inoculated intradermally with 30 mu g of FIV-pPPR plasmid DNA. For comparison, a fifth group received 10(3) TCID50 of a live virus stock of FIV-pPPR by intraperitoneal inoculation. Inoculation by im injection with 100 to 300 mu g of infectious FIV-pPPR proviral DNA produced infection detectable by both antiviral antibody and virus isolation from peripheral blood mononuclear cells. Inoculation by im injection with 30 mu g of proviral DNA resulted in infection in two of three inoculated cats. Intradermal injection with 30 mu g of proviral DNA induced infection in one of three cats. Induction of antiviral antibody and viremia was delayed in cats inoculated with 30 mu g compared to cats inoculated with either 100 or 300 mu g of proviral DNA. This study indicates that cloned FIV proviral DNA may replace infectious virion preparations as inocula for pathogenesis and immunization studies. (C) 1997 Academic Press.