Differential stimulation of helper and cytotoxic T cells by dendritic cells after infection by Yersinia enterocolitica in vitro.
Dendritic cells (DC) are antigen-presenting cells crucial for initiating immune responses like sensitization of T cells to foreign antigens. We have previously shown that infection of DC by enteropathogenic Yersinia enterocolitica in vitro leads to a transient suppression in the immunostimulatory capacity for autologous enriched total T cells. In this study, we found that killed Yersinia could replace live bacteria in this aspect, and that yersinial lipopolysaccharide (LPS)-antigen could be detected intracellularly over a time course of 8 days. A suppressive effect on T cell proliferation after stimulation with Yersinia-infected compared to uninfected DC was seen for CD4+ T cells isolated by immunomagnetic separation techniques over the whole time course of 8 days, whereas CD8+ T cells followed to exhibit a suppressed proliferation rate starting on day 5 post infection till the end of the time course. In contrast, enriched total T cells stimulated by Yersinia-infected DC showed weaker proliferation till day 6 post infection compared to stimulation by uninfected DC, but not thereafter. Mixing of purified CD4+ and CD8+ T cells at day 8 post infection could reconstitute the effect seen for enriched total T cells. Thus, helper in concert with cytotoxic T cells might contribute to the immune responses, that are necessary for control of Yersinia-infections.
Children's Hospital, University of Wuerzburg, 97080 Wuerzburg, Germany.
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Schoppet
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Huppertz
D017951:Antigen Presentation / Q000276:immunology; D002449:Cell Aggregation; D002455:Cell Division / Q000187:drug effects; D048429:Cell Size; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000382:microbiology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D018189:Immunomagnetic Separation; D015847:Interleukin-4 / Q000276:immunology / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D010835:Phytohemagglutinins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D013997:Time Factors; D015008:Yersinia enterocolitica / Q000166:cytology / Q000276:immunology* / Q000502:physiology*
D008070:Lipopolysaccharides; D010835:Phytohemagglutinins; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor