What Causes Isotype Switching

Isotype switching involves a replacement of the μ and δ heavy chain constant (CH) regions of the expressed Ig with γ, ε or α CH regions, and occurs by a DNA recombination event termed class switch recombination (CSR).

How does isotype switching occur?

Class switching occurs by a mechanism called class switch recombination (CSR) binding. Class switch recombination is a biological mechanism that allows the class of antibody produced by an activated B cell to change during a process known as isotype or class switching.

What happens during isotype switching?

During this process, the constant region portion of the antibody heavy chain is replaced with a different chain, but the variable region of the heavy chain stays the same. Therefore, isotype switching does not affecting antigen specificity. Instead, the antibody retains affinity for the same antigens.