       Document 0573
 DOCN  M9640573
 TI    Feline leukemia virus variants in experimentally induced thymic
       lymphosarcomas.
 DT    9604
 AU    Pandey R; Bechtel MK; Su Y; Ghosh AK; Hayes KA; Mathes LE; Roy-Burman P;
       Department of Pathology, University of Southern California School; of
       Medicine, Los Angeles 90033, USA.
 SO    Virology. 1995 Dec 20;214(2):584-92. Unique Identifier : AIDSLINE
       MED/96130198
 AB    This study was initiated to evaluate the in vivo infectivity and
       pathogenicity of a group of recombinant feline leukemia viruses (rFeLVs)
       previously generated by in vitro forced recombination between a FeLV
       subgroup A virus (FeLV-A) and an endogenous FeLV (enFeLV) envelope (env)
       element (Sheets et al., 1992, Virology 190, 849-855). To determine
       infectivity of rFeLVs, neonatal cats were inoculated with rFeLVs alone
       or in combination with FeLV-A. The recombinant viruses were able to
       replicate efficiently in vivo only when administered along with FeLV-A.
       Of six co-infected cats, three developed thymic lymphosarcomas, one
       severe aplastic anemia, and two cachexia and depression; all were
       viremic and seroconverted shortly after inoculation. While both virus
       types were detected in virtually all tissues examined from these
       tumor-bearing cats, there was a particularly noteworthy sequence
       reversion in the rFeLVs. It is known that exogenous FeLV isolates carry
       a conserved neutralizing MGPNL epitope in the middle of the surface
       glycoprotein domain of the env gene. In contrast, the parental
       recombinant viruses used to inoculate these cats harbored the
       enFeLV-derived MGPNP sequence at this position. However, all in
       vivo-propagated recombinants displayed the MGPNL sequence, while the
       env-encoded backbone flanking the MGPNL sequence was that of the
       parental recombinant virus. These results suggest that viruses with the
       MGPNL epitope have an in vivo proliferative advantage. The data also
       provide an explanation for the conservation of this epitope in exogenous
       FeLVs despite the existence of variant forms in enFeLV proviral elements
       with which they can recombine.
 DE    Amino Acid Sequence  Animal  Animals, Newborn  Base Sequence  Cats
       Crossing Over (Genetics)  DNA, Viral  Gene Products, env/GENETICS  Gene
       Products, gag/BLOOD/IMMUNOLOGY  Leukemia Virus,
       Feline/*GENETICS/ISOLATION & PURIF/PATHOGENICITY  Lymphoma,
       Diffuse/BLOOD/PATHOLOGY/*VIROLOGY  Molecular Sequence Data  Mutation
       Proviruses/GENETICS  Retroviridae Infections/BLOOD/PATHOLOGY/*VIROLOGY
       RNA, Viral/BLOOD  Support, U.S. Gov't, P.H.S.  Thymus
       Neoplasms/BLOOD/PATHOLOGY/*VIROLOGY  Tumor Cells, Cultured  Tumor Virus
       Infections/BLOOD/PATHOLOGY/*VIROLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

