title: Human T-cell responses to oral streptococci in human PBMC-NOD/SCID mice.
abstract: We investigated cellular and humoral immune responses to oral biofilm bacteria, including Streptococcus mutans, Streptococcus anginosus, Streptococcus sobrinus, and Streptococcus sanguinis, in NOD/SCID mice immunized with human peripheral blood mononuclear cells (hu-PBMC-NOD/SCID mice) to explore the pathogenicity of each of those organisms in dental and oral inflammatory diseases. hu-PBMC-NOD/SCID mice were immunized by intraperitoneal injections with the whole cells of the streptococci once a week for 3 weeks. FACS analyses were used to determine the percentages of various hu-T cell types, as well as intracellular cytokine production of interleukin-4 and interferon-gamma. Serum IgG and IgM antibody levels in response to the streptococci were also determined by enzyme-linked immunosorbent assay. S. anginosus induced a significant amount of the proinflammatory cytokine interferon-gamma in CD4(+) and CD8(+) T cells in comparison with the other streptococci. However, there was no significant differences between the streptococci in interleukin-4 production by CD4(+) and CD8(+) T cells after inoculation. Further, S. mutans significantly induced human anti-S. mutans IgG, IgG(1), IgG(2), and IgM antibodies in comparison with the other organisms. In conclusion, S. anginosus up-regulated Th1 and Tc1 cells, and S. mutans led to increasing levels of their antibodies, which was associated with the induction of Th2 cells. These results may contribute to a better understanding of human lymphocyte interactions to biofilm bacteria, along with their impact on dental and mucosal inflammatory diseases, as well as endocarditis.
authors.affiliation: Department of Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: M A
authors.initials: MA
authors.lastname: Salam
authors.forename: R
authors.initials: R
authors.lastname: Nakao
authors.forename: H
authors.initials: H
authors.lastname: Yonezawa
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Senpuku
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D017493:Leukocyte Common Antigens / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000637:transplantation; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D034363:Viridans Streptococci / Q000276:immunology* / Q000472:pathogenicity*
chemical_list: D000907:Antibodies, Bacterial; D015847:Interleukin-4; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens