IMMUNOLOGY

Detailed explanation-1: -Immunoglobulin class switching (or isotype switching, or isotypic commutation, or class switch recombination (CSR)) is a biological mechanism that changes a B cell’s production of antibody from one class to another; for example, from an isotype called IgM to an isotype called IgG.

Detailed explanation-2: -So a process needs to occur whereby this constant region gene is swapped from (IgM) to one of the other isotypes, without altering the variable heavy chain gene expression. This is done by a process called class switch recombination and is an irreversible process.

Detailed explanation-3: -Antibody-producing cells undergo a process of differentiation and class switch recombination (CSR) such that the antibodies produced start as immunoglobulin M (IgM) and then switch to IgG and IgA as the concentration of antigen changes and as the cells differentiate.