Dynamic signaling by T follicular helper cells during germinal center B cell selection

T and B cells' intricate molecular dance Generating high-affinity antibodies to fight infection is no easy task. To do so requires multiple steps, including T cells interacting with antibody-producing B cells in lymph nodes. These interactions select B cells expressing high-affinity antibodies for further proliferation, ensuring that the immune response generates high-affinity antibodies in large quantities. Shulman et al. use fluorescent live-cell imaging in mice to determine the molecular details of these interactions. They find that T cells engage B cells in short-lived mobile contacts during selection. These contacts cause T cells to flux calcium and produce proteins called cytokines, which probably drive B cells to proliferate and produce high-affinity antibodies. Science , this issue p. 1058