Delineation of protective epitopes on the E2-envelope glycoprotein of Semliki Forest virus (original) (raw)
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Journal of General Virology, 1991
Semliki Forest virus (SFV) infection of mice was used as a model to study the applicability of synthetic peptides containing only linear epitopes as viral vaccines. The identification of linear epitopes with vaccine potential on the E2 membrane protein of SFV was based on the binding of SFV-specific antibodies to a set of overlapping synthetic hexapeptides (Pepscan) representing the whole E2 amino acid sequence. The 14 available E2-specific monoclonal antibodies which were protective in vivo proved to be unsuitable for the identification of linear epitopes because they recognized only conformational epitopes, as indicated by their lack of reactivity with unfolded, reduced E2 protein on immunoblots. Three epitopes were detected with polyclonal anti-SFV serum at amino acid posi-tions 135 to 141,177 to 185 and 240 to 246 of the E2 protein. Synthetic peptides containing these epitopes were coupled to a carrier protein and tested as a vaccine. Mice immunized with the peptide containing amino acids 240 to 255 of protein E2 were protected against a challenge with virulent SFV but protection of mice immunized with the peptides containing amino acids 126 to 141 or 178 to 186 was only marginally better than that of controls. The prechallenge sera of most peptide-immunized mice reacted with SFVinfected cells but none of these sera neutralized the virus in vitro. However, protection of mice correlated well with SFV-specific antibody titre, suggesting antibody-mediated protection.
Serologically defined linear epitopes in the E2 envelope glycoprotein of Semliki Forest virus
Archives of Virology, 1990
A set of 41 overlapping peptides, representing the complete sequence of SFV-E2 protein were synthesized and analyzed in the ELISA test against murine anti-SFV sera. No single peptide was recognized by all antisera. Eight peptides were found to be highly reactive with hyperimmune anti-SFV sera. Six out of the eight peptide sequences coincide with the most hydrophilic regions of SFV-E2. Out of these, four peptides (amino acid positions 16-35, 61-80, 166-185, 286-305) that contain the least number of alphavirus conserved residues were selected. This panel constitutes the minimal number of peptides necessary and sufficient for specific recognition of hyperimmune mouse anti-SFV sera.
Journal of virology, 1993
The antibody response to a previously defined B-cell epitope of Semliki Forest virus (SFV) was investigated in male BALB/c (H-2d) mice. The B-cell epitope, located at amino acid positions 240 to 255 of the E2 protein, was linked to an H-2d-restricted T-helper cell epitope of SFV located at positions 137 to 151 of the E2 protein. Colinearly synthesized peptides, of either T-B or B-T polarity, mixed with different adjuvants (the nonionic block copolymer L 180.5, a water-oil-water [W/O/W] emulsion of L 180.5, Montanide, and Q VAC) were used for immunization. Generally, after one booster immunization, high serum antibody titers were measured against either peptide. With Q VAC and W/O/W L 180.5 as adjuvants, the titers of SFV-reactive (nonneutralizing) antibodies were consistently much higher after immunization with the T-B peptide than with the B-T peptide, which was reflected in a higher vaccine efficacy. With these two adjuvants, the survival ratio in T-B peptide-immunized mice was 82...
Journal of General Virology, 1992
A synthetic peptide that contains a Semliki Forest virus (SFV) B cell epitope, located at amino acid positions 240 to 255 of the E2 protein, and an SFV T helper (Th) cell epitope, located at positions 137 to 151 of the E2 protein, evoked high titres of SFV-reactive antibodies in H-2 d mice. Although the peptide-induced antibodies did not neutralize SFV in vitro, 70 to 100% of the peptide-immunized mice were protected against SFV, even when viral challenge was presented 4 months after immunization. The protection could be transferred by anti-peptide serum, indicating that antibodies were responsible for the protection. When the Th cell epitope of this protective peptide was replaced by an influenza virus Th cell epitope or by another SFV Th cell epitope, the resulting peptides induced lower non-neutralizing SFV-reactive antibody titres and protected a correspondingly lower percentage of mice (50% and 30%, respectively). A peptide with the same Th cell epitope as the best protective peptide but with a less effective SFV B cell epitope protected only 33% of the mice. These results indicate that protection against SFV by a synthetic peptide is primarily dependent on its ability to induce adequate amounts of antibodies with relevant specificity and sufficient affinity; the ability to induce a relevant (SFV-specific) T memory response played only a minor role in protection.
Vaccine, 1998
The humoral response to synthetic peptide vaccines against Semliki Forest virus (SFV) in H-2d BALB/c mice was investigated with the enzyme linked immunosorbent assay and the pepscan technique. The peptide vaccines consisted of amino acid sequences 240-255 (B) and 137-151 (T) of the E2 membrane protein of SFV colinearly synthesized in either orientation T-B or B-T. Sequence B contains an epitope inducing humoral immunity to lethal SFV infection and sequence T contains a H-2d restricted T-helper cell epitope. With sera from mice immunized subcutaneously with peptide T-B, and Quil A as adjuvant, two immunodominant B-cell epitopes were identified, FVPRAD, at position 240-246 and PHYGKEI, at position 145-151. However, with peptide B-T and Quil A as adjuvant for immunization the epitope PHYGKEI was clearly immunodominant, but antibodies elicited against this epitope were not reactive with SFV-infected L cells in contrast to the antibodies elicited by epitope FVPRAD. An additional epitope ...
Immunology, 1992
The rational development of peptide vaccines requires the identification of both B- and T-cell epitopes. In this study, potential T-helper cell epitopes of Semliki Forest virus (SFV) were identified on the basis of their ability to induce delayed-type hypersensitivity (DTH) in mice using recombinant SFV fragments produced as hybrid proteins with beta-galactosidase in Escherichia coli and synthetic peptides coupled to beta-galactosidase. Although the tested fragments spanned almost the entire amino acid sequence of the structural proteins of SFV, only one DTH-inducing region (located between amino acid 137 and 151 of the SFV E2 membrane protein) was identified. Peptides containing this E2 region stimulated lymph node cells from SFV-primed mice in vitro. The ability of the identified T-cell epitope to induce a specific T-helper response in mice was evaluated using synthetic peptides that contained combinations of the DTH-inducing region and different previously identified linear B-cel...
BackgroundLujo virus (LUJV) is a highly fatal human pathogen belonging to the Arenaviridae family. Lujo virus causes viral hemorrhagic fever (VHF). An In silico molecular docking was performed on the GPC domain of Lujo virus in complex with the first CUB domain of neuropilin-2.The aim of this study is to predict effective epitope-based vaccine against glycoprotein GPC precursor of Lujo virus using immunoinformatics approaches.Methods and Materialsglycoprotein GPC precursor of Lujo virus Sequence was retrieved from NCBI. Different prediction tools were used to analyze the nominee’s epitopes in BepiPred-2.0: Sequential B-Cell Epitope Predictor for B-cell, T-cell MHC class II & I. Then the proposed peptides were docked using Autodock 4.0 software program.Results and ConclusionsThe proposed and promising peptides FWYLNHTKL and YMFSVTLCI shows a very strong binding affinity to MHC class I & II alleles with high population coverage for the world, South Africa and Sudan. This indicates a s...
Journal of virology, 1981
When Semliki Forest virus temperature-sensitive mutant ts-3 was grown at the restrictive temperature an aberrant nascent cleavage of the 130,000-dalton structural polyprotein took place relatively frequently. This cleavage yielded an abnormal 86,000-dalton fusion protein (p86) consisting of the amino-terminal capsid protein linked to the amino acid sequences of envelope protein p62 (a precursor of E3 and E2). The other cleavage product was the carboxy-terminal envelope protein E1. p86 was not glycosylated and was sensitive to the action of protease in the microsomal fraction, whereas E1 was glycosylated and protected from proteases, indicating that it had been segregated into the cysternal side of the microsomal vesicles. All attempts to show the E1 protein at the cell surface have failed so far, suggesting that it remains associated with intracellular membranes. When ts-3-infected cells labeled at the restrictive temperature were shifted to the permissive temperature the only label...
Antibody Response to Spike Protein Vaccines Prepared from Semliki Forest Virus
Journal of General Virology, 1981
Subunit vaccines, containing the spike glycoproteins of Semliki Forest virus (SFV) in three different forms, have been prepared: detergent-solubilized monomers, detergent-and lipid-free octamers, and virosomes in which the spike proteins are reconstituted into phospholipid vesicles. Previous studies have shown that the octamers and the virosomes are very efficient in protecting mice against the encephalitis caused by virulent SFV (Morein et al., 1978). In this study we have characterized the specific antibody responses in mice vaccinated with the three SFV vaccines and correlated them with the protection against SFV encephalitis. The multimeric forms induced high humoral antibody titres; two doses of only 1 /tg protein gave rise to specific antibody titres of 0.6 mg/ml. The monomeric form was much less immunogenic.
Mechanisms of monoclonal antibody-mediated protection against virulent Semliki Forest virus
Journal of virology, 1985
Both neutralizing and nonneutralizing immunoglobulin G2a monoclonal antibodies (MAs) directed against the E2 glycoprotein of Semliki Forest virus (SFV) protected mice prophylactically and therapeutically against virulent SFV infection. The neutralizing MAs, however, conferred protection to mice at lower doses than did nonneutralizing MAs. The antibody-dependent, complement-mediated cytolysis of SFV-infected L cells was effectuated by both kinds of antibodies, but again neutralizing MAs were more effective. Removal of the Fc part of the neutralizing MA UM 5.1 by pepsin digestion resulted in a 100-fold reduction of the neutralization titer (10(4) versus 10(6)) and a complete loss of its capacity to mediate antibody-dependent, complement-mediated cytolysis. Passive protection of infected mice occurred only after administration of relatively high doses of F(ab')2 of MA UM 5.1 (30.0 micrograms versus 0.1 microgram). F(ab')2 fragments prepared from the nonneutralizing MA UM 4.2 ha...