Immunoglobulin class switch recombination (CSR)

Immunoglobulin class switch recombination (CSR), also known as antibody class switching or isotype switching, is a biological process that occurs in activated B cells, allowing them to change the class of antibody they produce (from IgM and IgD to IgG, IgA, or IgE) without altering the antigen specificity. This process involves a deletional recombination event between DNA switch (S) regions that are located upstream of the immunoglobulin heavy chain constant region genes. CSR is initiated by activation-induced cytidine deaminase (AID), which deaminates cytosines in S regions, leading to DNA breaks and recombination facilitated by DNA repair enzymes. The process is essential for a robust and tailored humoral immune response, enabling antibodies to interact with different effector molecules to combat pathogens more effectively. Dysregulation of CSR can contribute to immunodeficiencies or autoimmunity, but it is not itself a direct therapeutic target as it is a biological mechanism rather than a single molecule, receptor, or enzyme[1][2][3][6].

Other names

antibody class switchingimmunoglobulin class switchingisotype switchingisotypic commutation