Ee. Sparger et al., INFECTION OF CATS WITH MOLECULARLY CLONED AND BIOLOGICAL ISOLATES OF THE FELINE IMMUNODEFICIENCY VIRUS, Virology, 205(2), 1994, pp. 546-553
Molecularly cloned viruses are considered essential reagents for chara
cterizing viral domains responsible for infectivity and disease pathog
enesis in the host. The infectivity and hematological alterations asso
ciated with two molecularly cloned isolates of feline immunodeficiency
virus (FIV-pPPR and FIV-pF34) and an uncloned isolate (FIV-PPR) were
assessed by inoculation of cats. Inoculated cats were tested for viral
antibody, viremia, and clinical pathological disease. Peripheral bloo
d mononuclear cells isolated from inoculated cats were assayed for vir
us infection by virus isolation, amplification of proviral DNA (by pol
ymerase chain reaction), and in situ hybridizatioo for viral RNA. Over
50% of the cats inoculated with cloned Virus FIV-pF34 failed to seroc
onvert even when coinfected with feline leukemia virus; these cats wer
e consistently virus positive only by amplification of proviral DNA. A
ll cats inoculated with cloned virus FIV-pPPR seroconverted and were f
ound virus positive by at least two of three virus detection assays. B
oth cloned viruses were less capable of suppressing CD4:CD8 ratios whe
n compared to the biological isolates from which they were cloned. Iso
lates which replicate efficiently in feline peripheral blood mononucle
ar cells (PBMC), i.e., FIV-pPPR or biological FIV-PPR, caused greater
virus toad and lower CD4:CD8 ratios when compared to cloned FIV-pF34,
which replicates efficiently in feline adherent cell lines and macroph
ages but poorly in primary feline PBMC. Molecular clones FIV-pF34 and
FIV-pPPR will be useful reagents for characterization of viral determi
nants of virus load and possibly, cell tropism in vivo. (C) 1994 Acade
mic Press, Inc.