Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.

Descriptor ID	D000949
MeSH Number(s)	D12.776.395.550.509 D12.776.543.550.423 D23.050.301.500.400 D23.050.705.552.410
Concept/Terms	Histocompatibility Antigens Class II Histocompatibility Antigens Class II I-A-Antigen I A Antigen IA Antigen Antigen, IA Ia Antigens Antigens, Ia Ia-Like Antigens Antigens, Ia-Like Ia Like Antigens Class II Major Histocompatibility Antigens Immune-Response-Associated Antigens Antigens, Immune-Response-Associated Immune Response Associated Antigens Antigens, Immune Response Class II Antigen Antigen, Class II Class II Antigens Antigens, Class II Class II Histocompatibility Antigens I-A Antigen Antigen, I-A Immune Response Antigens Immune-Associated Antigens Immune-Associated Antigens Antigens, Immune-Associated Immune Associated Antigens

Below are MeSH descriptors whose meaning is more general than "Histocompatibility Antigens Class II".

Below are MeSH descriptors whose meaning is related to "Histocompatibility Antigens Class II".

Below are MeSH descriptors whose meaning is more specific than "Histocompatibility Antigens Class II".