The various rearrangements and splices create millions of possible antibodies. Similar processes result in production of millions of types of T cells. Class Switching IgM is the first immunoglobulin produced by a plasma cell when it is maturing. Production of IgM is influenced by soluble factors called cytokines that are produced by T cells. Class switching results in an antibody type with the same antigen specificity but a different function.
Class switching is accomplished by DNA cutting and rejoining.
The plasma cells may switch to yet another class later in their life, but they cannot return to one of the previous classes already produced. Figure 18.22 illustrates class switching. Figure 18.23 shows that specific cytokines can influence which immunoglobulin class is produced by the plasma cell.