immunoglobulin class switching

Immunoglobulin class switching, also known as isotype switching, isotypic commutation or class-switch recombination, is a biological mechanism that changes a B cell's production of immunoglobulin from one type to another, such as from the isotype IgM to the isotype IgG. During this process, the constant-region portion of the antibody heavy chain is changed, but the variable region of the heavy chain stays the same (the terms variable and constant refer to changes or lack thereof between antibodies that target different epitopes).