Activation-induced cytidine deaminase (AID) is a crucial enzyme in the adaptive immune system, primarily involved in the diversification of antibodies. It is a member of the apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) family of RNA/DNA editing enzymes . AID is encoded by the AICDA gene in humans and plays a central role in somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin genes .
AID’s primary function is to convert cytidine to uracil in DNA, which is a key step in SHM and CSR . This process is essential for generating high-affinity antibodies and enhancing the specificity of the immune response . AID’s activity is tightly regulated to prevent genomic instability, as its dysregulation can lead to increased mutation load, translocations, and lymphomagenesis .
AID is predominantly expressed in B lymphocytes, where it plays a critical role in the diversification of antibodies . After naïve B cells encounter antigens in secondary lymphoid tissues, AID initiates SHM and CSR, leading to the production of antibodies with higher affinity and different isotypes . This process is vital for the adaptive immune system to effectively combat infections .
While AID is essential for immune function, its misregulation can have severe consequences. Overexpression or deregulation of AID has been implicated in various cancers, particularly B-cell lymphomas . Chronic inflammation can lead to AID overexpression, resulting in mutations and epigenetic changes that drive carcinogenesis . Additionally, AID has been implicated in non-lymphoid cancers and autoimmune diseases .
Mouse anti-human AID antibodies are used in research to study the expression and function of AID in human cells. These antibodies are generated by immunizing mice with human AID protein, leading to the production of antibodies that specifically recognize and bind to human AID . These antibodies are valuable tools for investigating the role of AID in various biological processes and diseases .