Nucleotide sequence analysis and expression from recombinant vectors demonstrate that the attachment protein G of bovine respiratory syncytial virus is distinct from that of human respiratory syncytial virus.
Bovine respiratory syncytial (BRS) virus causes a severe lower respiratory tract disease in calves similar to the disease in children caused by human respiratory syncytial (HRS) virus. While there is antigenic cross-reactivity among the other major viral structural proteins, the major glycoprotein, G, of BRS virus and that of HRS virus are antigenically distinct. The G glycoprotein has been implicated as the attachment protein for HRS virus. We have carried out a molecular comparison of the glycoprotein G of BRS virus with the HRS virus counterparts. cDNA clones corresponding to the BRS virus G glycoprotein mRNA were isolated and analyzed by dideoxynucleotide sequencing. The BRS virus G mRNA contained 838 nucleotides exclusive of poly(A) and had a major open reading frame coding for a polypeptide of 257 amino acid residues. The deduced amino acid sequence of the BRS virus G polypeptide showed only 29 to 30% amino acid identity with the G protein of either the subgroup A or B HRS virus. However, despite this low level of identity, there were strong similarities in the predicted hydropathy profiles of the BRS virus and HRS virus G proteins. A cDNA molecule containing the complete BRS virus G major open reading frame was inserted into the thymidine kinase gene of vaccinia virus by homologous recombination, and a recombinant virus containing the BRS virus G protein gene was isolated. This recombinant virus expressed the BRS virus G protein, as demonstrated by Western immunoblot analysis and immunofluorescence of infected cells. The BRS virus G protein expressed from the recombinant vector was transported to and expressed on the surface of infected cells. Antisera to the BRS virus G protein made by using the recombinant vector to immunize animals recognized the BRS virus attachment protein but not the HRS virus G protein and vice versa, confirming the lack of antigenic cross-reactivity between the BRS and HRS virus attachment proteins. On the basis of the data presented here, we conclude that BRS virus should be classified within the genus Pneumovirus in a group separate from HRS virus and that it is no more closely related to HRS virus subgroup A than it is to HRS virus subgroup B.
Lerch
R A
RA
Department of Microbiology, University of Alabama Medical School, Birmingham 35294.
Anderson
K
K
Wertz
G W
GW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002417:Cattle; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000235:genetics; D012136:Respiratory Syncytial Viruses / Q000235:genetics*; D013045:Species Specificity; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology
C066028:G protein, Bovine respiratory syncytial virus; D012333:RNA, Messenger; D014759:Viral Envelope Proteins