Jason Cyster is interested in how immune cells organize in response to foreign invaders or malignant changes, while avoiding pathogenic responses to self-tissues and commensal microbiotas. Understanding this requires a precise knowledge of how immune cells position in tissues, and how they communicate. Cyster and his team focus on deciphering the molecular cues that guide immune cell movements and interactions within lymphoid organs, and the signals that prompt migration to other locations. They also investigate the requirements for mounting long-lived humoral immune responses. The team’s discoveries may help inform strategies for vaccine design, tumor immunotherapy, and treatment of autoimmune diseases.