The Regulation of T Cell Responses by a Subpopulation of CD8⁺DEC205⁺ Murine Dendritic Cells

Abstract

Dendritic cells (DC) are migratory bone-marrow-derived cells of sparse but broad tissue distribution^1,2. They are not homogeneous and even within a particular lymphoid organ distinct subpopulations can be separated^3–5. If procedures are used which extract all DC, both CD8α⁺ and CD8α⁻ DC can be isolated from mouse spleen⁵. Under these conditions the DC isolated from thymus are predominantly CD8⁺, whereas those isolated from lymph nodes (LN) are predominantly CD8⁻. This heterogeneity may be of functional importance, since there is evidence that the CD8⁺ DC of the thymus are of different developmental origin from the classical CD8⁻ DC typically found in LW^6,7. Since conventional isolation procedures yielded mainly the CD8⁻ DC population the functional capacity of CD8⁺ DC had not previously been explored. To determine whether CD8⁺ and CD8⁻ splenic DC differed in function, we tested their capacity to stimulate purified allogeneic CD4 and CD8 T cells in a primary mixed leucocyte reaction.