Dendritic cell

DCs link innate and adaptive immunity.

Plasmacytoid DCs
Type of DC that produces copious amounts of IFN in response to the detection of viral infection through its TLRs.

Myeloid DCs
Conventional DCs (professional APCs) process ingested pathogens and activate naive T cells.

Follicular DCs
Non-lymphoid cell in follicles of secondary lymphoid tissues.

Crucial in
 * Ag capture and presentation to B cells
 * B cell maturation
 * Formation of germinal centres
 * Selecting Ag-binding B cells during Ab responses

Immature DCs

 * highly phagocytic
 * poorly equipped as APCs; low expression of...
 * MHC class I and II
 * co-stimulatory molecules
 * chemokine receptors for migration and homing to lymphoid organs
 * cytokine production

Maturation process
After ingestion of Ag, maturation begins as DC leaves infection site and migrates to LN.

Express chemokine receptors (CCR7) for migration and entry to lymphoid tissues.

Upregulate expression of MHC I and II, co-stimulatory molecules and cell adhesion molecules.

Mature DCs are non-phagocytic and express the co-stimulatory molecule B7.