title: Identification of new candidate vaccine antigens made by Streptococcus pyogenes: purification and characterization of 16 putative extracellular lipoproteins.
abstract: Putative extracellular lipoproteins made by group A Streptococcus (GAS) are the focus of this study, which was designed to identify new candidate vaccine antigens. Bioinformatic analysis of a serotype M1 GAS strain identified 30 open-reading frames encoding putative lipoproteins. The genes encoding the mature form of 29 of these proteins were cloned, and 16 recombinant proteins were overexpressed in Escherichia coli and purified to apparent homogeneity. The genes encoding these 16 proteins were highly conserved in GAS strains for which genome sequence data are available (serotypes M1, M3, M5, M12, M18, and M28). Mice inoculated subcutaneously with GAS and humans with GAS pharyngitis and invasive infections seroconverted to most of the 16 recombinant proteins, which indicates that these lipoproteins were produced during infection. The blood of mice actively immunized with 5 of the 16 recombinant proteins had significantly (P<.05) increased growth-inhibitory activity, compared with the blood of unimmunized mice, which identified these proteins as potential new vaccine candidates.
authors.affiliation: Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: Benfang
authors.initials: B
authors.lastname: Lei
authors.forename: Mengyao
authors.initials: M
authors.lastname: Liu
authors.forename: Gillian L
authors.initials: GL
authors.lastname: Chesney
authors.forename: James M
authors.initials: JM
authors.lastname: Musser
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification*; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000378:metabolism; D019115:Fasciitis, Necrotizing / Q000097:blood; D006801:Humans; D008074:Lipoproteins / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification*; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010612:Pharyngitis / Q000097:blood; D011994:Recombinant Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013290:Streptococcal Infections / Q000097:blood / Q000517:prevention & control; D022541:Streptococcal Vaccines / Q000008:administration & dosage / Q000096:biosynthesis / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000235:genetics / Q000276:immunology*; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000096:biosynthesis / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D008074:Lipoproteins; D011994:Recombinant Proteins; D022541:Streptococcal Vaccines; D014614:Vaccines, Synthetic