Epitope mapping of envelope glycoprotein E1 of hog cholera virus strain Brescia

Abstract

Four antigenic domains (A, B, C and D) on envelope glycoprotein E1 (gp51-54) of hog cholera virus strain Brescia have been specified by using 13 monoclonal antibodies (MAbs) that recognize non-conserved and conserved epitopes. It was shown that the non-conserved epitopes map to the N-terminal half of E1 by analysis of chimeric E1 proteins of strains Brescia and C. Conserved epitopes, however, could not be mapped using this approach. Here we describe mapping of both conserved and non-conserved epitopes on E1 by the use of an extensive set of single and double deletion mutants of E1 of strain Brescia. Deletion mutants were transiently expressed in COS1 cells and analysed by immunostaining with the 13 MAbs directed against strain Brescia and four MAbs directed against strain C. All MAbs bound to the N-terminal half of El, i.e. amino acids 690 to 866 encoded by the sequence of strain Brescia. Domain B and one epitope in domain C are located between residues 690 and 773. Other epitopes in domain C are located on an extended region, i.e. between residues 690 and 800. Conserved epitopes of domain A are mapped between residues 766 and 866, whereas the only non-conserved epitope in this domain is located between residues 766 and 813. Domain D, represented by one MAb, is located in the same region as this nonconserved epitope of domain A, i.e. between residues 766 and 800. The results suggest the presence of two distinct antigenic units on El, one consisting of domains B and C and the other consisting of domain A.

Crystal structure of glycoprotein E2 from bovine viral diarrhea virus

“…The antibody reactivity of CSFV E2 has been studied in more detail than that of BVDV E2. Epitope mapping based on competitive antibody binding assays and neutralization-escape mutations has identified four distinct antigenic domains (A-D) (34). Domains A and D map to domain II in the BVDV E2 crystal structure; domains B and C correspond to domain I (Fig.…”

Deletions of Structural Glycoprotein E2 of Classical Swine Fever Virus Strain Alfort/187 Resolve a Linear Epitope of Monoclonal Antibody WH303 and the Minimal N-Terminal Domain Essential for Binding Immunoglobulin G Antibodies of a Pig Hyperimmune Serum

“…This can be achieved by expressing various truncated forms of the protein in E. coli and testing the reactivity of recombinant products with specific antibodies. A structural model for the CSFV E2, based upon the antigenic study with a panel of MAbs (35), predicted that the N-terminal part of E2 was surface exposed with a membrane-spanning region composed of a short stretch of C-terminal residues. Accordingly, the exposed region (aa 690 to 910) of E2, designated E2AB, was expressed and targeted for a series of deletion experiments to determine the binding site(s) recognized by WH303 or pig polyclonal IgG antibodies.…”

“…The protein contains four antigenic domains, A to D (33)(34)(35)38), which are located within the N-terminal half of the protein. A linear epitope that is highly conserved among pestiviruses was mapped to high resolution at the C-terminal region of CSFV E2 (40).…”

N-Linked Glycosylation Status of Classical Swine Fever Virus Strain Brescia E2 Glycoprotein Influences Virulence in Swine

“…Putative N-glycosylation sites within CSFV E2 have been predicted previously (23,42). According to a glycosylation analysis algorithm (http://www.cbs.dtu.dk/services/), E2 of the CSFV strain Brescia has five putative N-linked sites and one putative O-linked glycosylation site, although this is not confirmed by experimental evidence.…”