The Synthesis of Immunogenic Polypeptides Encoded by Tick-borne Encephalitis Virus

Abstract

SUMMARYTick-borne encephalitis virus codes for two major immunogenic polypeptides, one of which is the major virion envelope protein E, and the other, NV3, does not have a designated function at present. The intracellular forms of both the E and NV3 polypeptides contain at least four types of sugar residues, i.e. galactose, glucosamine, fucose and mannose. The only glycoprotein in the extracellular virion particles is E. Experiments performed in the presence of tunicamycin have demonstrated that most of these sugars are N-linked. The kinetics of synthesis of E and NV3 have been studied and both show a distinct lag period between initiation of protein synthesis and the appearance of either protein.

The NS1 protein of tick-borne encephalitis virus forms multimeric species upon secretion from the host cell

“…The Neudorfl isolate of TBE virus was grown in PS cells infected with seed virus grown in suckling mouse brain as described previously (Stephenson et al, 1987).…”

“…The most important exception is the major non-structural glycoprotein NS I. This protein has a polypeptide backbone with a Mr ranging from 46K to 51K (Stephenson et al, 1987;Smith & Wright, 1985;Gould et al, 1986), but is extensively glycosylated, especially in its secreted form (Lee et al, 1989;Mason, 1989;Flamand et al, 1992). Most of the intracellular forms of NS1 contain oligosaccharide side chains in the high mannose form, but at least one glycosylation site in the secreted form contains sugars added in the Golgi apparatus (Lee et al, 1989).…”

The Synthesis and Maturation of a Non-structural Extracellular Antigen from Tick-borne Encephalitis Virus and Its Relationship to the Intracellular NS1 Protein

“…The polypeptide with an apparent Mr of 58K corresponds in mobility to a similar species (E) found in infected cells (Fig. 1, lane 4) and virions (Heinz & Kunz, 1977;Stephenson et aL, 1987). The virion capsid protein (C) was seen migrating with an apparent Mr of 16K but the minor envelope protein M could not be detected.…”

“…This time-lag probably reflects the time taken for the protein to travel through the Golgi apparatus to intracellular vesicles and the time taken for these vesicles to reach the cell surface. It is of interest that although NS1 is synthesized after E (Stephenson et al, 1987) the appearance of these two proteins in the extracellular medium is simultaneous.…”

“…Antibody T9 which displays neutralization and protective activities (Phillpotts et al, 1985(Phillpotts et al, , 1986 reacts only with the E glycoproteins of virus particles (Stephenson et al, 1987), the 58K intracellular polypeptide and the 58K extracellular polypeptide (Fig. 2a).…”