title: Differences in recognition of wild-type and lipoprotein-deficient strains of oral Streptococci in vitro and in vivo.
abstract: Whole cells of wild-type strains of Streptococcus gordonii and Streptococcus mutans induced Toll-like receptor 2 (TLR2)-mediated nuclear factor-κB (NF-κB) activation, whereas those of lipoprotein (LP)-deficient strains did not. All strains upregulated the proliferation of TLR2(+/+) splenocytes more strongly than TLR2(-/-) splenocytes. However, significant differences were not observed between the cytokine-inducing activities of wild-type and LP-deficient strains toward TLR2(+/+) and TLR2(-/-) splenocytes. Muramyl dipeptide as well as whole cells not only induced nucleotide-binding oligomerization domain 2 (NOD2)-mediated activation of NF-κB but also enhanced the proliferation of TLR2(-/-) as well as TLR2(+/+) splenocytes. Wild-type strains of these streptococci were more resistant to clearance from blood and organs (liver and spleen) in TLR2(+/+) but not TLR2(-/-) mice and induced production of larger amounts of blood TNF-α than the LP-deficient strains. Wild-type strains of both species adhered to human vascular endothelial cells more strongly than did the LP-deficient strains. Thus, this study suggested that LP plays an important role in the recognition of these streptococci by the host in vivo as well as in vitro and that these streptococci possess some components recognized by NOD2 and/or TLR2 that are involved in the mitogenic activity toward splenocytes.
authors.affiliation: Division of Oral Molecular Microbiology, Department of Oral Pathobiological Science, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Segawa
authors.forename: Ayumi
authors.initials: A
authors.lastname: Saeki
authors.forename: Akira
authors.initials: A
authors.lastname: Hasebe
authors.forename: Takafumi
authors.initials: T
authors.lastname: Arimoto
authors.forename: Hideo
authors.initials: H
authors.lastname: Kataoka
authors.forename: Atsuro
authors.initials: A
authors.lastname: Yokoyama
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kawanami
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Shibata
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001769:Blood / Q000382:microbiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D042783:Endothelial Cells / Q000382:microbiology; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008074:Lipoproteins / Q000172:deficiency / Q000276:immunology*; D008099:Liver / Q000382:microbiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009055:Mouth / Q000382:microbiology; D016328:NF-kappa B / Q000276:immunology*; D013154:Spleen / Q000276:immunology / Q000382:microbiology; D054773:Streptococcus gordonii / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D013295:Streptococcus mutans / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D051195:Toll-Like Receptor 2 / Q000172:deficiency / Q000276:immunology*
chemical_list: D016207:Cytokines; D008074:Lipoproteins; D016328:NF-kappa B; C493486:Tlr2 protein, mouse; D051195:Toll-Like Receptor 2
keywords: Streptococci; Toll-like receptor 2; lipoprotein