Dynamic Control of Self-Specific CD8 super(+) T Cell Responses via a Combination of Signals Mediated by Dendritic Cells

• Published in: Journal of Immunology 2007-09, Vol.179 (5), p.2870-2879
• Main Authors: Raveney, Ben JE, Morgan, David J
• Format: Article
• Language: English
• ISSN: 0022-1767; 1365-2567

It is acknowledged that T cell interactions with mature dendritic cells (DC) lead to immunity, whereas interactions with immature DC lead to tolerance induction. Using a transgenic murine system, we have examined how DC expressing self-peptides control naive, self-reactive CD8 super(+) T cell responses in vitro and in vivo. We have shown, for the first time, that immature DC can also stimulate productive activation of naive self-specific CD8 super(+) T cells, which results in extensive proliferation, the expression of a highly activated cell surface phenotype, and differentiation into autoimmune CTL. Conversely, mature DC can induce abortive activation of naive CD8 super(+) T cells, which is characterized by low-level proliferation, the expression of a partially activated cell surface phenotype which does not result in autoimmune CTL. Critically, both CD8 super(+) T cell responses are determined by a combination of signals mediated by the DC, and that altering any one of these signals dramatically shifts the balance between autoimmunity and self-tolerance induction. We hypothesize that DC maintain the steady state of self-tolerance among self-specific CD8 super(+) T cells in an active and dynamic manner, licensing productive immune responses against self-tissues only when required.