References
PMID:8642276 PMID:24457417 PMID:11154916 PMID:11509172 PMID:22076556
DENDRITIC_CELL
PMID:11154916, PMID:11509172, PMID:22076556
Processed antigen peptide in lysosomes forms complex with MHC-class-II. formation and transport to the cell surface of MHC-class-II???peptide complexes is induced by maturation.
Immature DCs in culture can take up antigen but do not present it efficiently to T cells. After detecting microbial products or proinflammatory cytokines, immature DCs transform into mature DCs, cells with a reduced capacity for antigen uptake but now with an exceptional capacity for T cell stimulation.
PMID:22790179, PMID:14508489
The presentation of exogenous antigens on MHC class I molecules, known as cross-presentation, is essential for the initiation of CD8+ T cell responses. In vivo, cross-presentation is mainly carried out by specific dendritic cell (DC) subsets through an adaptation of their endocytic and phagocytic pathways.
After phagocytosis, antigens are exported into the cytosol and degraded by the proteasome4, 5, 6. The resulting peptides are thought to be translocated into the lumen of the endoplasmic reticulum (ER) by specific transporters associated with antigen presentation (TAP), and loaded onto MHC class I molecules by a complex ???loading machinery??? (which includes tapasin, calreticulin and Erp57)