Figure 24-41. An example of the DNA rearrangement that occurs in class switch recombination.

Figure 24-41An example of the DNA rearrangement that occurs in class switch recombination

A B cell making an IgM antibody from an assembled VDJ DNA sequence is stimulated by antigen and the cytokines made by helper T cells to switch to making an IgA antibody. In the process, it deletes the DNA between the VDJ sequence and the Cα-coding sequence. Specific DNA sequences (switch sequences) located upstream of each CH-coding sequence recombine with each other to delete the intervening DNA. Class switch recombination is thought to be mediated by a switch recombinase,which is directed to the appropriate switch sequences when these become accessible under the influence of cytokines, as we discuss later.

From: The Generation of Antibody Diversity

Cover of Molecular Biology of the Cell
Molecular Biology of the Cell. 4th edition.
Alberts B, Johnson A, Lewis J, et al.
New York: Garland Science; 2002.
Copyright © 2002, Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter; Copyright © 1983, 1989, 1994, Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts, and James D. Watson .

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.