Scientists at the University of Freiburg have discovered a new protein, Kidins220/ARMS, in B cells. They also determined that it plays a critical role in the production of antibodies and the formation of B cells.
Various teams of researchers had already noted that Kidins220/ARMS is present in nerve cells and in T cells of the immune system. However, its presence in B cells was unknown until now.
“We've discovered a new molecular player in the immune system,” said immunobiologist Wolfgang Schamel, adding, “This knowledge could help to develop new medications for autoimmune diseases or other illnesses in the future.”
A postdoc from the Schamel lab, Gina J. Fiala, Ph.D., is the lead author of the group's study (“Kidins220/ARMS binds to the B cell antigen receptor and regulates B cell development and activation) in the Journal of Experimental Medicine. Dr. Fiala studied Kidins220/ARMS in B cells for her doctoral thesis.
B cells, which are the only cells to produce antibodies, carry B cell receptors. These activate the B cells when an antigen is found by the immune system. The scientific team discovered that Kidins220/ARMS interacts with the B cell receptor and affects signaling pathways from the receptor to the interior of the cell. Without Kidins220/ARMS, the receptor's ability to send signals is limited. As a result, the B cells manufacture less antibodies and the immune system is weakened.
Kidins220/ARMS is also vital for the formation of B cells. If a mouse cannot produce this protein, the B lymphocytes develop in a way that makes them less functional than the B cells of a healthy immune system. The reason for this is that B cells depend on the signals from the B cell receptor and pre-B cell receptor, which is the early version of a B cell receptor, at various stages of their development. Deficiency in Kidins220/ARMS therefore obstructs the development of B cells.