The dominant role of CD8+ dendritic cells in cross-presentation is not dictated by antigen capture.

Mouse spleens contain three populations of conventional (CD11c(high)) dendritic cells (DCs) that play distinct functions. The CD8(+) DC are unique in that they can present exogenous antigens on their MHC class I molecules, a process known as cross-presentation. It is unclear whether this special ability is because only the CD8(+) DC can capture the antigens used in cross-presentation assays, or because this is the only DC population that possesses specialized machinery for cross-presentation.

The protease inhibitor cystatin C is differentially expressed among dendritic cell populations, but does not control antigen presentation.

Dendritic cells (DC) undergo complex developmental changes during maturation. The MHC class II (MHC II) molecules of immature DC accumulate in intracellular compartments, but are expressed at high levels on the plasma membrane upon DC maturation. It has been proposed that the cysteine protease inhibitor cystatin C (CyC) plays a pivotal role in the control of this process by regulating the activity of cathepsin S, a protease involved in removal of the MHC II chaperone Ii, and hence in the formation of MHC II-peptide complexes.

Dendritic cells constitutively present self antigens in their immature state in vivo and regulate antigen presentation by controlling the rates of MHC class II synthesis and endocytosis.

Dendritic cells (DCs) change their antigen-presenting properties during maturation. Immature DCs efficiently capture antigens, but are reported to be impaired in their processing and presenting capacity. Upon an encounter with an inflammatory stimulus, DCs undergo a maturation process that leads to efficient presentation of antigens captured at the time of activation, but precludes processing of antigens encountered at later time points.

Most lymphoid organ dendritic cell types are phenotypically and functionally immature.

Dendritic cells (DCs) have been thought to follow a life history, typified by Langerhans cells (LCs), with 2 major developmental stages: an immature stage that captures antigens in the periphery and a mature stage that presents those antigens in the lymphoid organs. However, a systematic assessment of the maturity of lymphoid organ DCs has been lacking. We have analyzed the maturity of the DC types found in the steady state in the spleen, lymph nodes (LNs), and thymus.