Isolation and sequencing of infectious clones of feline foamy virus and a human/feline foamy virus Env chimera

Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan 1 Department of Immunology, National Institute of Infectious Disease, Tokyo 113-8657, Japan 2 Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan 3 Central Laboratory, Kyoritu Shouji Co. Ltd, Ibaraki, Japan 4 Author for correspondence: Yoichi Fujii. Fax +81 52 836 3430. e-mail fatfuji{at}hotmail.com Full-length DNAs of the Coleman and S7801 strains (pSKY3.0, pSKY5.0) of infectious feline foamy viruses (FFVs) were cloned and sequenced. Parental viruses, designated SKY3.0 and SKY5.0, were secreted following transfection of Crandell feline kidney (CRFK) cells. Production of the rescued parental viruses was enhanced in the presence of trichostatin A. Amino acid sequence similarities between FFV and human foamy virus (HFV) are extremely low for the envelope protein and capsid antigen, as predicted from the two clones. However, a chimeric FFV clone was constructed with the HFV Env substituted for the FFV Env. The chimeric virus (HFFV, SKY4.0) was able to infect and replicate in CRFK cells as well as in peripheral blood mononuclear cells of cats in vivo . Consequently, the chimeric HFFV may be useful for the creation of FV vectors for gene transfer strategies.