Is MHC 1 endogenous or exogenous?
Is MHC 1 endogenous or exogenous?
Class I MHC (MHC-I) molecules present primarily endogenous antigens, i.e. antigens that are present in the cytosol and are subject to the cytosolic processing mechanisms that comprise the conventional MHC-I processing pathway.
Which class of MHC proteins presents exogenous antigens?
There is also so called cross-presentation in which exogenous antigens can be presented by MHC class I molecules. Endogenous antigens can also be presented by MHC class II when they are degraded through autophagy. Figure 1.
Is MHC 2 endogenous or exogenous?
Antigenic peptides presented by major histocompatibility complex (MHC) class II molecules are generally derived from exogenous proteins acquired by antigen presenting cells. However, in some circumstances, MHC class II molecules can present intracellular proteins expressed within the antigen-presenting cells.
What is exogenous pathway of antigen presentation?
The exogenous pathway is utilized by specialized antigen-presenting cells to present peptides derived from proteins that the cell has endocytosed. The peptides are presented on MHC class II molecules. Proteins are endocytosed and degraded by acid-dependent proteases in endosomes; this process takes about an hour.
What are endogenous and exogenous antigen?
Endogenous antigens are antigens found within the cytosol of human cells such as viral proteins, proteins from intracellular bacteria, and tumor antigens. Exogenous antigens are antigens that enter from outside the body, such as bacteria, fungi, protozoa, and free viruses.
Where does most exogenous antigen presentation?
Most exogenous antigen presentation to T cells occurs in lymphoid tissues and organs located throughout the body, to which it is transported by dendritic cells.
What is the process of antigen presentation?
Antigen processing and presentation is the process by which protein antigen is ingested by an antigen-presenting cell (APC), partially digested into peptide fragments and then displayed on the surface of the APC associated with an antigen-presenting molecule such as MHC class I or MHC class II, for recognition by …
What are the pathways of antigen presentation?
Major Pathways of Antigen Cross-Presentation In general, there are two main cross-presentation pathways: the vacuolar pathway and the endosome-to-cytosol pathway (Figure 1). In the vacuolar pathway, antigen processing and loading onto MHC I molecules occurs within the endo/lysosomal compartment.
What is exogenous antigen?
Exogenous antigens are antigens that have entered the body from the outside, for example, by inhalation, ingestion or injection. The immune system’s response to exogenous antigens is often subclinical.
What is endogenous antigen presentation?
Antigen presentation is a vital immune process that is essential for T cell immune response triggering. If there has been an infection with viruses or bacteria, the cell will present an endogenous or exogenous peptide fragment derived from the antigen by MHC molecules.
How do antigen-presenting cells process endogenous antigens?
Antigens generated endogenously within these cells are bound to MHC-I molecules and presented on the cell surface. This antigen presentation pathway enables the immune system to detect transformed or infected cells displaying peptides from modified-self (mutated) or foreign proteins.
What are exogenous antigens?
Exogenous antigens are antigens that enter from outside the body, such as bacteria, fungi, protozoa, and free viruses. These exogenous antigens enter macrophages, dendritic cells, and B-lymphocytes through phagocytosis or pinocytosis.
