Backstage with a command performer

Some cells sing with the chorus, while others unwittingly achieve fame on their own. The immune system’s B cell is a true diva that spends its early days preparing for the ultimate audition. Its repertoire of possible antibodies to invading microbes totals 50 million. For the immune system, this repertoire means the difference between destroying a potentially lethal antigen or not. Since the late 1970s, the genes for making immunoglobulin, a family of blood proteins that compose the antibodies, sufficed to explain the B cell’s vast oeuvre. A B cell that is mature enough to respond to antigen does so by combining genes in a process called immunoglobulin gene rearrangement. Many possible combinations during this process allow a wide catalog of antibodies to literally take shape. Now, a biochemical phenomenon involving changes to stationary proteins in the B cell’s nucleus, called histones, is known also to contribute to the cell’s various solo performances.