Are CD8+ 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, Süss, G
• Format: Journal Article
• Language: English
• Published: England Oxford Publishing Limited (England) 01.07.1997
• Subjects: AIDS/HIV; Animals; CD4-Positive T-Lymphocytes - immunology; CD8 Antigens - physiology; CD8-Positive T-Lymphocytes - immunology; Cell Count; Cell Differentiation - immunology; Cell Separation; Dendritic Cells - immunology; Dendritic Cells - metabolism; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout
• DOI: 10.1093/intimm/9.7.1061
• ISSN: 0953-8178; 1460-2377

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+ and DEC-205- 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+ DC from either CD8-/- or CD8+/+ mice was similar and was much less than the response to DEC-205- 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+ DEC-205+ 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.