The dendritic cell populations of mouse lymph nodes

The dendritic cells (DC) of mouse lymph nodes (LN) were isolated, analyzed for surface markers, and compared with those of spleen. Low to moderate sta ining of LN DC for CD4 and low staining for CD8 was shown to be attributabl e to pickup of these markers from T cells. Excluding this artifact, five LN DC subsets could be delineated. They included the three populations found in spleen (CD4(+)8(-)DEC-205(-), CD4(-)8(-)DEC-205(-), CD4(-)8(+)DEC-205(+) ), although the CD4-expressing DC were of low incidence. LN DC included two additional populations, characterized by relatively low expression of CD8 but moderate or high expression of DEC-205. Both appeared among the DC migr ating out of skin into LN, but only one was restricted to skin-draining LN and was identified as the mature form of epidermal Langerhans cells (LC). T he putative LC-derived DC displayed the following properties: large size; h igh levels of class II MHC, which persisted to some extent even in CIITA nu ll mice; expression of very high levels of DEC-205 and of CD40; expression of many myeloid surface markers; and no expression of CD4 and only low to m oderate expression of CD8. The putative LC-derived DC among skin emigrants and in LN also showed strong intracellular staining of langerin.