Inhibition of pestivirus infection in cell culture by envelope proteins E(rns) and E2 of classical swine fever virus: E(rns) and E2 interact with different receptors.

Abstract

Pure preparations of envelope glycoproteins E rns and E2 of classical swine fever virus (CSFV) synthesized in insect cells were used to study infection of porcine and bovine cells with the pestiviruses CSFV and bovine viral diarrhoea virus (BVDV). Almost 100 % inhibition of infection of porcine kidney cells with CSFV was produced by 100 µg/ml E rns . After removal of the virus no E rns was needed in the overlay medium (growth medium) to maintain this level of inhibition. In contrast, 100 % inhibition of infection of porcine kidney cells with CSFV by 10 µg/ml E2 was only achieved when E2 was added to the overlay medium. When E2 was omitted, a maximum of 50 % inhibition was achieved. This indicated that after the virus and E2 were removed from the cells, infection still occurred, by virus

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

“…However, very little is known about the role of glycosylation in the function of pestivirus glycoproteins. A previous study that examined the closely related pestivirus BVDV E2 glycoprotein expressed in a baculovirus/insect cell system (26) showed that the pattern of glycosylation affects the ability of the isolated glycoprotein to prevent infection of calf testis cells with BVDV, an otherwise inhibitory effect observed with wildtype E2 protein (14). The same study also showed that modification of N1 and N3 sites in BVDV E2 impaired expression and secretion of the protein in insect cells, suggesting that glycosylation at those sites is essential for correct folding and subsequent secretion of E2.…”

“…E2 is the most immunogenic of the CSFV glycoproteins (15,40,44), inducing neutralizing antibodies and protection against lethal CSFV challenge. E2 has been implicated, along with E rns (14) and E1 (43), in viral adsorption to host cells; indeed, chimeric pestiviruses exhibit infectivity and cell tropism phenotypes consistent with those of the E2 gene donor (18,40). Modifications introduced into these glycoproteins appear to have an important effect on CSFV virulence (21,29,31,41).…”

Formation of bovine viral diarrhea virus E1–E2 heterodimers is essential for virus entry and depends on charged residues in the transmembrane domains

“…The genome consists of a single open reading frame, which is translated into a polyprotein that is co-and post-translationally cleaved into structural and non-structural proteins (Rümenapf et al, 1993). The structural proteins comprise the nucleocapsid C protein and three envelope glycoproteins, E rns , E1 and E2, of which at least E rns and E2 are postulated to be responsible for virus attachment and/or cell entry (Donis & Dubovi, 1987;Hulst & Moormann, 1997). E1 is assumed to function as a membrane anchor for E2 (Rümenapf et al, 1993).…”

Alteration of a Second Putative Fusion Peptide of Structural Glycoprotein E2 of Classical Swine Fever Virus Alters Virus Replication and Virulence in Swine

“…E2 is considered essential for CSFV replication, as virus mutants containing partial or complete deletions of the E2 gene are nonviable (7). E2 has been implicated, along with E rns (8) and E1 (9), in viral adsorption to host cells (10,11). Modifications introduced into this glycoprotein appear to have an important effect on CSFV virulence (12)(13)(14)(15)(16).…”