A major neutralizing domain maps within the carboxyl-terminal half of the cleaved cytomegalovirus B glycoprotein.
Cytomegalovirus (CMV) encodes several glycoproteins reported to be structural homologues of glycoproteins encoded by herpes simplex virus type 1 (HSV-1). To map the antigenic and functional domains on the 907 amino acid CMV glycoprotein B (gB), we cloned and expressed a subfragment of BamHI fragment R of the CMV (Towne) genome into an expression vector and reacted the resulting gene product with a panel of monoclonal antibodies. Our results showed that the DNA fragment encodes related glycoproteins which we previously designated gA and which others have reported to be homologous to HSV-1 gB in CMV (AD169). Analyses of the processing of CMV gB transiently expressed in eukaryotic cells showed that glycosylation occurred independently of viral infection. Ten antibodies with complement-dependent and independent neutralizing activity reacted with a truncated derivative of gB that contained 619 amino-terminal residues but lacked the transmembrane and intracellular regions of the molecule. Twelve additional antibodies reacted with a CHO cell line expressing a 680 amino-terminal derivative of gB. All of the reactive antibodies precipitated the 447 residue carboxy-terminal cleavage product of gB from extracts of CMV-infected cells. These results showed that the neutralizing epitopes map in at least two domains of gB which are located in a discontinuous segment of 219 amino acids between residues 461 and 680 from the amino terminus of the molecule.
Banks
T
T
Department of Stomatology, School of Dentistry, University of California, San Francisco 94143.
Huo
B
B
Kousoulas
K
K
Spaete
R
R
Pachl
C
C
Pereira
L
L
D003587:Cytomegalovirus / Q000235:genetics* / Q000276:immunology; D004279:DNA, Viral / Q000032:analysis; D000939:Epitopes / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006801:Humans; D015183:Restriction Mapping; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology
D004279:DNA, Viral; D000939:Epitopes; D014759:Viral Envelope Proteins; C040495:glycoprotein B, Simplexvirus