Mapping of linear B cell epitopes on capsid proteins of bovine papillomavirus: identification of three external type-restricted epitopes.
Immunodominant, conserved and type-restricted external epitopes of bovine papillomavirus (BPV) major (L1) capsid protein have been identified using BPV particles and synthetic peptides. Antisera to disrupted BPV-1 recognized BPV-1 and BPV-2 particles in immune electron microscopy (IEM) studies and inhibited BPV-2-induced focus formation of NIH/3T3 cells. Thus BPV-1/BPV-2 cross-reactive epitopes occur on the surface of virions. The L1 protein appeared to be immunodominant as the antisera reacted with three dominant BPV-1/BPV-2 conserved B cell epitopes (amino acids 111 to 125, 131 to 145 and 191 to 205) in Pepscan assays of BPV-1 L1, whereas no common epitopes and less frequent antibody binding to peptides were detected in Pepscans of the L2 protein of BPV-1. Four discrete variable regions were identified in the sequences of L1 proteins of BPV-1 and BPV-2. Antisera against synthetic peptides corresponding to three of the four variable regions (amino acids 42 to 56, 435 to 449 and 485 to 499) of BPV-2 L1 caused clumping of BPV-2, but not of BPV-1, particles as examined by IEM, and antisera to one peptide (amino acids 485 to 499) inhibited BPV-2-induced focus formation of NIH/3T3 cells. These data suggest that these regions are type-specific BPV-2 L1 epitopes and that they occur on the virion surface. Although conformation-dependent epitopes remain to be identified on papillomaviruses, the linear epitopes identified in this study may be worthy of further study as constituents of experimental prophylactic vaccines.
Cason
J
J
Richard Dimbleby Laboratory of Cancer Virology, Rayne Institute, London, U.K.
Kambo
P K
PK
Jewers
R J
RJ
Chrystie
I L
IL
Best
J M
JM
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology*; D052688:Bovine papillomavirus 1 / Q000276:immunology* / Q000648:ultrastructure; D002213:Capsid / Q000276:immunology*; D036022:Capsid Proteins; D003429:Cross Reactions; D016056:Immunodominant Epitopes; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013045:Species Specificity; D010948:Viral Plaque Assay
D000914:Antibodies, Viral; D036022:Capsid Proteins; D016056:Immunodominant Epitopes; C085217:L1 protein, Bovine papillomavirus; C085218:L2 protein, Bovine papillomavirus; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins