An alpha chain of antigen-presenting major histocompatibility complex class II molecule. In complex with the beta chain HLA-DRB, displays antigenic peptides on professional antigen presenting cells for recognition by alpha-beta T cell receptor on HLA-DR-restricted CD4-positive T cells. This guides antigen-specific T-helper effector functions, both antibody-mediated immune response and macrophage activation, to ultimately eliminate the infectious agents and transformed cells . Typically presents extracellular peptide antigens of 10 to 30 amino acids that arise from proteolysis of endocytosed antigens in lysosomes . In the tumor microenvironment, presents antigenic peptides that are primarily generated in tumor-resident APCs likely via phagocytosis of apoptotic tumor cells or macropinocytosis of secreted tumor proteins . Presents peptides derived from intracellular proteins that are trapped in autolysosomes after macroautophagy, a mechanism especially relevant for T cell selection in the thymus and central immune tolerance . The selection of the immunodominant epitopes follows two processing modes: 'bind first, cut/trim later' for pathogen-derived antigenic peptides and 'cut first, bind later' for autoantigens/self-peptides . The anchor residue at position 1 of the peptide N-terminus, usually a large hydrophobic residue, is essential for high affinity interaction with MHCII molecules .

HLA class II histocompatibility antigen, DR alpha chain (MHC class II antigen DRA)

p01903

Human

WB,IHC,IF,ICC,FC

WB 1:1000-1:5000
IHC 1:100-1:1000
IF 1:200-1:500
ICC 1:200-1:500
FC 1:20-1:50

~29 kD

Rabbit

50mM Tris-Glycine(pH 7.4), 0.15M NaCl, 40% Glycerol, 0.01% sodium azide and 0.05% BSA.

Store at -20°C. Stable for 12 months from date of receipt.