title: Oligoclonal CD4+ T cells promote host memory immune responses to Zwitterionic polysaccharide of Streptococcus pneumoniae.
abstract: Zwitterionic polysaccharides of the normal flora bacteria represent a novel class of antigens in that they correct systemic CD4(+) T-cell deficiencies and direct lymphoid organogenesis during colonization of the host. Presentation of these polysaccharides to CD4(+) T cells depends on major histocompatibility complex class II- and DM-dependent retrograde transport from lysosomes to the cell surface. Yet the phenotype and clonality of the immune response to the polysaccharide in the mature host immune system have not been studied. Using the zwitterionic capsular polysaccharide Sp1 of Streptococcus pneumoniae, a transient member of the bacterial flora, in an experimental mouse model of cellular immunity, we demonstrated the accumulation of TH1- and TH17-polarized CD4(+) CD44(high) CD62(low) CD25(-) memory T cells. Subcutaneous immunization with Sp1 resulted in an increase of serum immunoglobulin G (IgG), predominantly of the IgG1 subclass, and suggested the presence of a humoral memory response to the polysaccharide. CD4(+) T cells stimulated with polysaccharide in vitro and in vivo showed a nonrestricted pattern for the T-cell receptor (TCR) beta-chain variable region, as demonstrated by semiquantitative reverse transcription-PCR and flow cytometry. Clonotype mapping of in vivo and in vitro polysaccharide-activated CD4(+) T cells revealed clonotypic TCR transcripts. Taken together, the data show the induction of clonal expansion of CD4(+) T cells by polysaccharides of commensal bacteria. Cellular and humoral memory host responses imply the ability of these polysaccharides to mediate the expansion of T cells via recognition within the CDR3 region of the TCR.
authors: Institute for Medical Microbiology, Immunology and Hygiene, Medical Center, University of Cologne, 50935 Cologne, Germany.
authors: Laura
authors: L
authors: Groneck
authors: David
authors: D
authors: Schrama
authors: Mario
authors: M
authors: Fabri
authors: Tom Li
authors: TL
authors: Stephen
authors: Fabian
authors: F
authors: Harms
authors: Sonja
authors: S
authors: Meemboor
authors: Helena
authors: H
authors: Hafke
authors: Martina
authors: M
authors: Bessler
authors: Jürgen C
authors: JC
authors: Becker
authors: Wiltrud M
authors: WM
authors: Kalka-Moll
mesh_terms: D000038:Abscess / Q000209:etiology; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D020381:Interleukin-17 / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D020381:Interleukin-17; D011135:Polysaccharides, Bacterial