What Is a Peptide Antigen?
The exogenous antigen is combined with APC (antigen-presenting cells) and internalized to form an endosome. In the endosome or lysosome, the antigen is degraded by the protease into a polypeptide, and a small amount of the polypeptide is combined with the MHC molecule to form the antigen peptide-MHC. A molecular complex, in which the degraded polypeptide is an antigenic peptide.
Antigen peptide
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- Chinese name
- Antigen peptide
- Solid
- Peptide or antigen-derived peptide
- Types of
- inside and outside
- Alias
- Endogenous antigen
- The exogenous antigen is combined with APC (antigen-presenting cells) and internalized to form an endosome. In the endosome or lysosome, the antigen is degraded by the protease into a polypeptide, and a small amount of the polypeptide is combined with the MHC molecule to form the antigen peptide-MHC. A molecular complex, in which the degraded polypeptide is an antigenic peptide.
- Antigen peptide generally refers to a polypeptide or antigen-derived peptide that is immunogenic. The distinction between endogenous antigens (peptides) and exogenous antigens (peptides) is determined according to their position before entering the processing pathway, that is, located inside the cell or outside the cell. Any antigen, whether it is its own or non-existent, such as processing in the cytoplasm, is called an endogenous antigen, and those that enter the endosome for processing are called exogenous antigens. Therefore, self-proteins, such as soluble MHC molecules, or cell membrane-bound protein molecules, are processed by endosomes after being taken up by APC. Although they are self-proteins, they are also called exogenous antigens, otherwise they are replicated in host cells. Viruses, viral proteins produced in host cells, and pathogens of intracellular infections are non-self proteins, but because of their presence in the cytoplasm, they are also called endogenous antigens. The site where exogenous antigens and endogenous antigens are processed in cells, the types of MHC that are bound, and the compartments that bind to MHC molecules are completely different. The enzymes involved in processing and the cells needed for intracellular transport Signals or accompanying proteins are also different.