Subgroup specific protection of mice from respiratory syncytial virus infection with peptides encompassing the amino acid region 174-187 from the G glycoprotein: the role of cysteinyl residues in protection.
We identified subgroup specific protective epitopes represented by the amino acid regions 174-187 and 171-187 of the G glycoproteins from respiratory syncytial virus (RSV), subgroups A and B. Mice immunized with coupled synthetic peptides corresponding to either the region 174-187 containing a Cys186-->Ser substitution or to the native region 171-187 were completely resistant to RSV infection but only to the respective virus. The protective activities of the peptides 174-187 were dependent on the Cys186-->Ser substitution. In addition, a recombinant protein representing the region 125-203 of the A subgroup G glycoprotein expressed in Escherichia coli was capable without further treatment to completely protect animals against RSV subgroup A infection. We show that the combinations of cysteinyl residues (positions 173, 176, 182, and 186) retained within either synthetic peptides or the recombinant protein G125-203 greatly influenced their protective activities. This indicates that the region 171-187 is essential for the protection conferred by the G125-203 protein. Furthermore, our results strongly suggest that the peptides' and recombinant protein's potencies are a function of a loop-like structure which is stabilized by intramolecular disulfide linkages between Cys176-Cys182 and Cys173-Cys186. This is further supported by the observation that chemical blocking of the sulfidryl groups in synthetic peptides completely eliminated their protective activity.
Simard
C
C
Institut Armand-Frappier, Centre de recherche en virologie, Laval des Rapides, Québec, Canada.
Nadon
F
F
Séguin
C
C
Thien
N N
NN
Binz
H
H
Basso
J
J
Laliberté
J F
JF
Trudel
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000096:biosynthesis / Q000276:immunology*; D001483:Base Sequence; D002478:Cells, Cultured; D003545:Cysteine / Q000276:immunology* / Q000502:physiology; D000939:Epitopes / Q000276:immunology; D004926:Escherichia coli / Q000378:metabolism; D015707:HN Protein; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D011499:Protein Processing, Post-Translational / Q000276:immunology; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology* / Q000517:prevention & control*; D012136:Respiratory Syncytial Viruses / Q000145:classification / Q000276:immunology*; D013045:Species Specificity; D013438:Sulfhydryl Compounds / Q000276:immunology; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000096:biosynthesis / Q000276:immunology*
D000956:Antigens, Viral; D000939:Epitopes; D015707:HN Protein; D010455:Peptides; D013438:Sulfhydryl Compounds; D014759:Viral Envelope Proteins; D014764:Viral Proteins; C116204:attachment protein G; D003545:Cysteine