Co-stimulatory functions of antigen-presenting cells.
Antigen-presenting cells, in addition to presenting processed antigen, provide co-stimulatory signals that are necessary for stimulating maximal lymphokine production by CD4+ T cells. For interleukin 2 (IL-2)-producing CD4+ T cells, the B7 molecule provides an important co-stimulatory signal through interaction with its ligand on the T-cell surface, CD28. Populations of antigen-presenting cells that express high levels of B7 (e.g., dendritic cells) are much more potent stimulators of T-cell activation than cells that fail to express B7 (e.g., resting B cells). An increase in B7 expression could therefore explain the increased accessory function gained by Langerhans cells as they leave the skin and migrate to the draining lymph node.
Johnson
J G
JG
Department of Microbiology, University of Minnesota Medical School, Minneapolis 55455.
Jenkins
M K
MK
D000938:Antigen-Presenting Cells / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation