title: Enolase from Streptococcus sobrinus is an immunosuppressive protein.
abstract: A strategy of Streptococcus sobrinus, a major agent of dental caries, to survive and colonize the host consists of the production of a protein that suppresses the specific antibody responses. We have cloned the gene coding for a protein with immunosuppressive activity. It contains an open reading frame of 1302 base pairs encoding a polypeptide with 434 amino acid residues and a molecular mass of 46910 Da. The gene product is homologous to enolases from several organisms. The polypeptide was expressed in Escherichia coli as a hexahistidine-tagged protein and purified in a fluoride-sensitive enzymatically active form. Pretreatment of mice with the S. sobrinus recombinant enolase suppresses a primary immune response against T-cell dependent antigens. This immunosuppressive effect is specific to the antigen used in the immunization, as it is not observed when the immune response against other antigens is analysed. Furthermore, the S. sobrinus recombinant enolase stimulates an early production of interleukin-10, an anti-inflammatory cytokine, and not the pro-inflammatory cytokine IFN-gamma. These observations indicate that enolase acts in the suppression of the specific host immune response against S. sobrinus infection.
authors.affiliation: Instituto de Ciências Biomédicas de Abel Salazar, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Veiga-Malta
authors.forename: Margarida
authors.initials: M
authors.lastname: Duarte
authors.forename: Márcia
authors.initials: M
authors.lastname: Dinis
authors.forename: Delfina
authors.initials: D
authors.lastname: Tavares
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Videira
authors.forename: Paula
authors.initials: P
authors.lastname: Ferreira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000008:administration & dosage / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D007108:Immune Tolerance; D007114:Immunization; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010751:Phosphopyruvate Hydratase / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D016986:Streptococcus sobrinus / Q000201:enzymology* / Q000276:immunology / Q000472:pathogenicity
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D016753:Interleukin-10; D007371:Interferon-gamma; D010751:Phosphopyruvate Hydratase