Final answer:
Class switch recombination (CSR) is a process in B cells during the immune response. It involves rearrangement of constant region gene segments, allowing for antibody class switching. AID enzyme initiates breaks in DNA for gene segment exchange.
Step-by-step explanation:
Class switch recombination (CSR) is a process that occurs in B cells during the immune response. It involves a genetic rearrangement of the constant region gene segments, which allows for the switch in antibody production from one class (such as IgM) to another class (such as IgG, IgA, or IgE). This process is important for the adaptive immune system to produce different types of antibodies that can better target specific pathogens.
CSR is guided by a DNA recombination enzyme called activation-induced cytidine deaminase (AID). AID initiates breaks in the DNA of the B cell's antibody gene locus, leading to the exchange of constant region gene segments. The specific class of antibody produced by a B cell is determined by which constant region gene segment it chooses to switch to.
Overall, class switch recombination allows for the production of diverse antibody classes, enabling the immune system to effectively respond to different types of pathogens.