An antigen-presenting cell ( APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs).
In addition to the MHC family of proteins, antigen presentation relies on other specialized signaling molecules on the surfaces of both APCs and T cells. Antigen-presenting cells are vital for effective adaptive immune response, as the functioning of both cytotoxic and helper T cells is dependent on APCs.
Jump to navigation Jump to search. Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells. An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation.
However, it has been observed that antigen presentation to CD4+ cells via MHC class II is not restricted to the classically professional APCs. Other leukocytes, including granulocytes such as mast cells and neutrophils, can be induced to do so, as can endothelial and epithelial cells under certain circumstances.
MHC (known as human leukocyte antigen [HLA] in humans) class I molecules display peptides derived from antigens expressed in intracellular compartments to cytotoxic CD8 T cells, and class II molecules exhibit peptides from extra-cellular sources to helper CD4 T cells [6,7].
The main difference between MHC class 1 and 2 is that MHC class 1 molecules present antigens to cytotoxic T cells with CD8+ receptors whereas MHC class 2 molecules present antigens to helper T cells with CD4+ receptors.
Cloned dendritic cells can present exogenous antigens on both MHC class I and class II molecules.
MHC Class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells.
Their main role is in antigen presentation where MHC molecules display peptide fragments for recognition by appropriate T-cells. This is an important process in the immune system response for destroying invading pathogens.
Abstract. The main function of major histocompatibility complex (MHC) class II molecules is to present processed antigens, which are derived primarily from exogenous sources, to CD4(+) T-lymphocytes. MHC class II molecules thereby are critical for the initiation of the antigen-specific immune response.
The MHC Class II signaling during the cognate B–T cells interaction contributes to the early antigen-specific IgM production. Anti-MHC class II mAbs induce cell death in malignant B cells.
Trophoblast cells are unique because they are one of the few mammalian cell types that do not express major histocompatibility complex (MHC) class II antigens, either constitutively or after exposure to IFN-γ.
The expression of MHC class II (MHC-II) on the surface of antigen-presenting cells, such as dendritic cells (DCs), is tightly regulated during cellular activation. Many cells, including DCs, are activated following stimulation of innate Toll-like receptors (TLRs) by products of microorganisms.
Abstract. Complete T cell activation requires at least two signals. The first is delivered through the antigen-specific T cell receptor, whereas the second is generated by cognate interactions through adhesion molecules of T cells and antigen-presenting cells and/or by cytokines produced by antigen-presenting cells.
Antigen presentation serves to ensure adaptive immune responses are initiated to invading microorganisms. Therefore, in an effort to survive in the host, pathogens target antigen presentation pathways and disable their function.
An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs).