Development of a Western Blot Assay for Detection of Bovine Immunodeficiency-Like Virus Using Capsid and Transmembrane Envelope Proteins Expressed from Recombinant Baculovirus

Abstract

A 120-amino-acid polypeptide selected from the transmembrane protein region (tTM) and the major capsid protein p26 of bovine immunodeficiency-like virus (BIV) were expressed as fusion proteins from recombinant baculoviruses. The antigenic reactivity of both recombinant fusion proteins was confirmed by Western blot with bovine and rabbit antisera to BIV. BIV-negative bovine sera and animal sera positive for bovine syncytial virus and bovine leukemia virus failed to recognize the recombinant fusion proteins, thereby showing the specificity of the BIV Western blot. One hundred and five bovine serum samples were tested for the presence of anti-BIV antibodies by the recombinant protein-based Western blot and a reference Western blot assay using cell culture-derived virions as test antigens. There was a 100% concordance when the p26 fusion protein was used in the Western blot. However, the Western blot using the tTM fusion protein as its test antigen identified four BIV-positive bovine sera which had tested negative in both the p26 recombinant-protein-based and the reference Western blot assays. This resulted in the lower concordance of 96.2% between the tTM-protein-based and reference Western blot assays. The results of this study showed that the recombinant p26 and tTM proteins can be used as test antigens for the serodetection of BIV-infection in animals.

The molecular biology of bovine immunodeficiency virus: a comparison with other lentiviruses

“…In contrast, immune reactivity to the envelope TM protein of BIV, which appears later in the course of BIV infection, was still detectable at the end of the experiment period (up to 3.5 or 4 years after infection). These results are in accordance with our own data, in which immune reactivity to the BIV TM was detected in cattle whose sera failed to recognize the p26 protein (Abed et al, 1999;Abed and Archambault, 2000). Whether these changes in antibody production reflect differences in the apparently differential expression of the gag and env gene products in vivo late in infection is at present unknown.…”

“…In these infected rabbits, BIV was rescued from PBMC and spleen, lymph nodes and brain by the cocultivation method (Pifat et al, 1992). Moreover, a rapid and long-lasting virus-specific humoral immune response was observed in rabbits infected with BIV (Abed et al, 1999;Abed and Archambault, 2000). No clinical symptoms were observed in BIV-infected animals during all these studies.…”

“…The BIV proviral DNA is 8960 nucleotides long and resembles other retroviruses with the typical 5Ј-3Ј gag, pol and env gene arrangement. These genes encode viral structural proteins, namely the gag-encoded capsid p26 protein (p26) and the above- mentioned env-encoded SU and TM proteins, which are highly immunogenic (Abed et al, 1999;Abed and Archambault, 2000), and enzymes such as the reverse transcriptase, integrase and protease necessary for the synthesis and integration of the provirus DNA into the host cell genome, and for viral polyprotein processing, respectively (Gonda et al, 1994). The proviral genome has two flanking sequences, called long terminal repeats (LTRs), used in the regulation of viral replication and gene expression (Gonda et al, 1994).…”

The contribution of bovines to human health against viral infections

“…Calves experimentally infected with BIV R-29 isolates displayed intermittent lymphocytosis and lymphadenopathy without any obvious clinical indications (Carpenter et al 1992 ; Onuma et al 1992 ; Suarez et al 1993 ). Virus-specific antibodies found in calves against BIV R-29 strain (Whetstone et al 1990 ) were primarily to p26, which is the most immunodominant protein of BIV (Abed et al 1999 ). Also, cattle infected with BLV produced antibodies that can inhibit HIV-1 reverse transcriptase activity in vitro (Gillet et al 2007 ).…”

Comparison of immunoassay and real-time PCR methods for the detection of Jembrana disease virus infection in Bali cattle

“…Capsid antigens are often used in these assays since antibodies to this protein develop first and are usually highly conserved within each lentiviral group (Burki et al, 1992;Houwers and Nauta, 1989;Zanoni et al, 1991). Recombinant CA and truncated transmembrane (TM) proteins have been used for the detection of BIV infections using Western blot assays (Abed et al, 1999). An immunodominant epitope was identified in the N-terminal portion of BIV TM (Chen et al, 1994) and a TM peptide ELISA was developed from peptide mapping this region (Scobie et al, 1999).…”