How do dendritic cells activate T cells?

The T cell encounters a dendritic cell (DC) bearing its cognate peptide in an MHC molecule, and binds the peptide-MHC though CD3 and CD4 or 8. This induces full activation and effector function in the T cell.

What happens when dendritic cells are activated?

Once activated, they migrate to the lymph nodes where they interact with T cells and B cells to initiate and shape the adaptive immune response. At certain development stages they grow branched projections, the dendrites that give the cell its name (δένδρον or déndron being Greek for ‘tree’).

What is the role of MHC in T cell activation?

Antigen-presenting cells display three types of protein molecules on their surface that have a role in activating a T cell to become an effector cell: (1) MHC proteins, which present foreign antigen to the T cell receptor, (2) costimulatory proteins, which bind to complementary receptors on the T cell surface, and (3) …

Do dendritic cells activate helper T cells?

The dendritic cells then migrate to a peripheral lymphoid organ and activate naïve helper T cells to differentiate into either TH1 or TH2 effector cells, depending on the cytokines the dendritic cells produce.

Can dendritic cells activate B cells?

B cells are efficiently activated by antigens presented on cell membranes, which provide opportunity for receptor cross-linking and antigen capture. There is mounting evidence, however, that conventional dendritic cells (cDC) can also participate in native antigen presentation to B cells.

What signals activate dendritic cells?

Dendritic cells (DCs) are responsible for initiating a subsequent phase of immunity, dominated by the action of pathogen-specific T and B cells. As for the early pro-inflammatory response, DC activation is triggered by PRR signals.

What cytokines activate dendritic cells?

Several cytokines are able to trigger DCs activation (maturation) either in autocrine or paracrine fashion including IL-1, TNF, type I IFNs and TSLP (right panel).

Do dendritic cells have MHC class I and II?

MHC I are found on all nucleated body cells, and MHC II are found on macrophages, dendritic cells, and B cells (along with MHC I).

Do dendritic cells express MHC class 1?

Dendritic cells (DCs) have the unique ability to pick up dead cells carrying antigens in tissue and migrate to the lymph nodes where they can cross-present cell-associated antigens by MHC class I to CD8+ T cells.

What is the relation of CD4 and CD8 with MHC complexes?

CD4 and CD8 enhance T cell signaling by binding MHC class II (CD4) or MHC class I (CD8) molecules on APCs. The interaction of CD4 with MHC class II greatly reduces the number of antigenic peptides required for T cell activation (5) and substantially increases cytokine production by helper T cells (1).

What is the role of MHC molecules in the recognition of infected cells by NK cells and what is the physiologic significance of this recognition?

The loss of inhibitory signaling by MHC-specific receptors is responsible for the capacity of NK cells to attack class I-deficient cells. Because inhibitory receptors discriminate allelic variants of class I molecules, NK cells also attack MHC-different cells.