Long lasting protection from harmful pathogens depends on collaboration of multiple types of immune cells each with a unique function. These cells interact with each other in small confined niches in lymphoid organs and exchange molecular signals required for differentiation into cells with the capacity to eliminate invading pathogens. Protective antibodies evolve in lymphoid organs in sites known as germinal centers. In our lab we examine how interactions between immune cells promote antibody affinity maturation and differentiation of B cells into long lived memory and antibody forming cells.