Are CD8 super(+) dendritic cells (DC) veto cells? The role of CD8 on DC in DC development and in the regulation of CD4 and CD8 T cell responses

• Published in: International immunology Vol. 9; no. 7; pp. 1061 - 1064
• Main Authors: Kronin, V, Vremec, D, Winkel, K, Classon, B J, Miller, R G, Mak, T W, Shortman, K, Suess, G
• Format: Journal Article
• Language: English
• Published: 01.07.1997
• ISSN: 0953-8178

The CD8-expressing dendritic cells (DC) present in mouse spleen have been shown to have a regulatory effect on the CD4 and CD8 T cells they activate, restricting subsequent T cell proliferation by either inducing apoptotic T cell death (CD4 T cells) or by limiting endogenous cytokine production (CD8 T cells). To determine the role of the CD8 molecule itself in these regulatory phenomena, the DC from CD8 null mice were studied. The DC marker DEC-205 (NLDC 145) was used as a surrogate marker for CD8, since the expression of these two molecules on splenic DC was closely correlated. DC levels were normal, and the incidence of DEC-205 super(+) and DEC-205 super(-) DC was normal in CD8 null mice, indicating that the absence of CD8 did not affect DC development. The proliferative response of T cells to allogeneic DEC-205 super(+) DC from either CD8 super(-/-) or CD8 super(+/+) mice was similar and was much less than the response to DEC-205 super(-) DC from these mice. This applied to both the CD4 and the CD8 T cell responses. Thus the lack of the CD8 molecule did not affect the stimulatory or regulatory properties of the DC. The regulatory CD8 super(+) DEC-205 super(+) DC therefore differ in that respect from antigen-presenting 'veto' cells, where CD8 itself is involved in transmitting negative signals to the T cells. DEC-205 may prove to be a more pertinent marker of the regulatory DC population.