What is HLA-Ⅱ molecule?

According to the location and function of genes, the main histocompatibility complexes are divided into three categories, namely MHC, MHC and MHC.

MHC class I (MHC I): Located on the surface of general cells, it can provide some information in general cells. For example, if a cell is infected by a virus, the amino acid peptide of the outer membrane fragment of the virus is indicated outside the cell through MHC, which can be recognized by killer CD8+ T cells for elimination.

MHCⅱ: Most of them are located on antigen presenting cells (APC), such as macrophages. This rule is what happens outside the cell. For example, if there is bacterial invasion in the tissue, macrophages will use MHC to promote bacterial fragments to enter helper T cells and start immune response.

Extended data

Structural characteristics of MHC gene

(1) Polygeneity: The gene complex consists of several closely adjacent gene loci, and the encoded products have the same or similar functions.

For example, mouse H-2: 17 chromosome: the short arm of chromosome 6 (6P2 1.3 1) has a total length of 3600-4000kb and 224 gene loci (128 works).

Functional genes, 96 pseudogenes).

(2) Polymorphism: There are two or more alleles at the same HLA locus in the population.

Significance of MHC polymorphism;

References:

Baidu Encyclopedia-Major histocompatibility complex