I-Ab Monoclonal Antibody (25-9-3), PE, Invitrogen™

Description

• I-Ab (H2-Ab1, histocompatibility 2, class II antigen A, beta 1) is an MHC class II heterodimer molecule of non-covalently associated alpha (31-34 kDa) and beta (26-29 kDa) chains
• Major histocompatibility complex class II antigen presentation requires the participation of lysosomal proteases in two convergent processes
• First, the antigens endocytosed by the antigen presenting cells must be broken down into antigenic peptides
• Second, class II molecules are synthesized with their peptide-binding site blocked by invariant chain (Ii), and they aquire the capacity to bind antigens only after Ii has been degraded in the compartments where peptides reside
• MHC class II molecules present exogenously derived antigen to CD4+ T lymphocytes, which are usually T helper cells
• CD4 interacts with non-polymorphic residues of MHC class II
• H2-Ab1 heterodimer chains alpha (DQA) and beta (DQB) are both anchored in the membrane
• H2-Ab1 plays a central role in the immune system by presenting peptides derived from extracellular proteins
• Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages)
• The beta chain contains 6 exons
• Exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, exon 4 encodes the transmembrane domain and exon 5 encodes the cytoplasmic tail
• Within the DQ molecule both the alpha chain and the beta chain contain the polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules
• Typing for polymorphisms is routinely done for bone marrow transplantation
• HLA and MHC antibodies play a significant role in Immunopeptidomics, facilitating the identification and characterization of neoantigens through high-performance liquid chromatography coupled to tandem Mass Spectrometry.