Preclinical evaluation of a vaccine based on conserved region of M protein that prevents group A streptococcal infection.
OBJECTIVE
Infection with group A Streptococcus (GAS) may result in a number of human diseases ranging from the relatively benign pharyngitis to the potentially life-threatening invasive diseases and post-infectious sequelae. We have previously defined a minimal B-cell epitope from the conserved region of the M-protein. Here we report on the immunogenicity, opsonic potential of the resulting sera and the level of protection induced by this peptide in comparison to a pepsin extract of the M protein.


METHODS
Inbred mice were immunized with peptides derived from the M protein. Sera were collected from the immunized mice and its opsonic potential determined for M1 and M6 GAS strains. Mice were then intranasally challenged with a virulent M1 GAS strain to determine the protective efficacy of the peptides.


RESULTS
The peptides induced significant antibody responses when delivered subcutaneously and immunized mice demonstrated significantly enhanced survival compared to control groups following challenge.


CONCLUSIONS
The data obtained in the present study indicated that the chimeric peptide J8 from the conserved region of the M protein could form the basis for an anti-streptococcal vaccine in future.
Batzloff
Michael
M
Cooperative Research Centre for Vaccine Technology, The Queensland Institute of Medical Research, Post Office Royal Brisbane Hospital, QLD 4029, Australia. michaelBa@qimr.edu.au
Yan
Huaru
H
Davies
Mark
M
Hartas
Jon
J
Good
Michael
M
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D002352:Carrier Proteins / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D013290:Streptococcal Infections / Q000517:prevention & control*
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D002352:Carrier Proteins; C014689:streptococcal M protein