Differential Stimulation of Helper and Cytotoxic T Cells by Dendritic Cells after Infection by Yersinia enterocolitica in Vitro

Author： Schoppet M. Huppertz H-I.

Publisher： Academic Press

ISSN： 0008-8749

Source： Cellular Immunology, Vol.208, Iss.1, 2001-02, pp. : 43-51

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Abstract

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.