Reactivity of primate sera to foamy virus Gag and Bet proteins

Abstract

In order to establish criteria for the serodiagnosis of foamy virus infections we investigated the extent to which sera from infected individuals of human and primate origin react with structural and non-structural virus proteins in immunoblot assays. Using lysates from infected cells as the source of virus antigen, antibodies were preferentially detected against the Gag proteins and the non-structural Bet protein. Both the Gag precursor molecules of 70 and 74K apparent M r and the cytoplasmic 60K M r Bet protein were found to be phosphorylated, the latter being synthesized in large amounts in infected cells. Rabbit antiserum raised against recombinant human foamy virus (HFV) Gag major capsid protein cross-reacted with foamy viruses of chimpanzee, gorilla, orang-utan, rhesus monkey and African green monkey origin. This was reflected by a broad cross-reactivity of the respective monkey sera to the Gag proteins of the various foamy virus isolates. Cross-reactivity of antisera against the Bet protein was restricted to viruses from man and the great apes. Recombinant Gag and Bet proteins expressed in prokaryotes or in insect cells were readily recognized by foamy virus-positive primate sera. Screening serum samples from chimpanzees with HFV Gag and Bet proteins expressed by recombinant baculoviruses revealed that 18 out of 35 (52 %) were positive for Gag antibodies. Of these, 13 (72%) showed antibodies against the Bet protein, indicating that Bet antigen is of value in serological screening for foamy virus infections.

An active foamy virus integrase is required for virus replication.

“…However, to obtain this result, two nontemplated nucleotides, which were complementary to the terminal U5 dinucleotide, were added to the U3 substrate (Pahl & Flu$ gel, 1993). In addition, their introduction would destroy the bet reading frame overlapping the ppt-U3 border in all FVs Kupiec et al, 1991 ;Renne et al, 1992 ;Baunach et al, 1993 ;Hahn et al, 1994 ;Renshaw & Casey, 1994 b ;Herchenro$ der et al, 1994 ;Helps & Harbour, 1997 ;Winkler et al, 1997). Therefore, we suggest that the report of Pahl & Flu$ gel (1993) showed that FV IN is able to cleave some kind of elongated U3 end, which may arise through the generation of untidy ends during reverse transcription.…”

“…pHSRV2 or mutant plasmids were transfected into BHK\bel-1 cells, and 4 days later a cellular lysate was prepared in detergent buffer as described (Hahn et al, 1994). Following separation in SDS-8 % polyacrylamide gel and semi-dry blotting to nitrocellulose membranes (Schleicher & Schu$ ll), the viral proteins were allowed to react with Gag-specific, and following stripping of the blot with RNaseHspecific, rabbit antisera (Hahn et al, 1994 ;Ko$ gel et al, 1995) and stained using the ECL system (Amersham).…”

Pattern of seroreactivity against feline foamy virus proteins in domestic cats from Germany

“…FV infections are persistent and infected animals show a sustained antibody response against Gag and Bet that is used for serological identification of infected hosts via ELISA and/or immunoblotting ( , [Hahn et al, 1994], [Heneine et al, 2003], [Khan and Kumar, 2006], [Saib, 2003] and [Williams and Khan, 2010]). Virus can commonly be isolated from infected cats, cattle and non-human primates ( , [Heneine et al, 2003], [Khan and Kumar, 2006], [Romen et al, 2007], [Saib, 2003] and [Williams and Khan, 2010]); however, no disease was associated with infections and thus, FVs are therefore considered apathogenic ( [Linial, 2000] and [Saib, 2003]).…”

Foamy virus–adenovirus hybrid vectors

“…22 It was detectable in HC-FAD-2-and HC-FAD-7-transduced cells (Figure 3a). In HC-FAD-8-transduced cells only the pr71 Gag precursor was stained, because p68 Gag is derived from protease-mediated cleavage of pr71 HC-FAD-7 is only able to perform the internal retrotransposition pathway of cells initially transduced by the hybrid vector.…”

“…22 Following centrifugation through the Qiashredder (Qiagen) to destroy high molecular weight (MW) nucleic acids, the proteins were separated in 7.5% polyacrylamide gels (SDS-PAGE) in a tricine buffer system. After blotting, the gels were reacted with mouse monoclonal antibodies (MABs) against PFV Gag and Pol proteins, 9,40,41 a rabbit antiserum against the PFV Env LP, 23 or with an MAB against human b-actin (Sigma).…”