title: Analysis of factors affecting surface expression and immunogenicity of recombinant proteins expressed by gram-positive commensal vectors.
abstract: Several key protein structural attributes were altered in an effort to optimize expression and immunogenicity of a foreign protein (M protein from Streptococcus pyogenes) exposed on the surface of Streptococcus gordonii commensal bacterial vectors: (i) a shorter N-terminal region, (ii) the addition of a 94-amino-acid spacer, and (iii) the addition of extra C-repeat regions (CRR) from the M6 protein. A decrease in the amount of cell surface M6 was observed upon deletion of 10 or more amino acid residues at the N terminus. On the other hand, reactivity of monoclonal antibody to surface M6 increased with the addition of the spacer adjacent to the proline- and glycine-rich region, and an increase in epitope dosage was obtained by adding another CRR immediately downstream of the original CRR. The results obtained should facilitate the design of improved vaccine candidates using this antigen delivery technology.
authors.affiliation: SIGA Technologies Inc., Corvallis, Oregon 97333, USA.
authors.forename: Tové C
authors.initials: TC
authors.lastname: Bolken
authors.forename: Christine A
authors.initials: CA
authors.lastname: Franke
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Jones
authors.forename: Richard H
authors.initials: RH
authors.lastname: Bell
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Swanson
authors.forename: David S
authors.initials: DS
authors.lastname: King
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Fischetti
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Hruby
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology; D005822:Genetic Vectors; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000276:immunology; D020449:Repetitive Sequences, Amino Acid; D013291:Streptococcus / Q000235:genetics* / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D007074:Immunoglobulin G; D011994:Recombinant Proteins; C014689:streptococcal M protein