A study coordinated by Luís Graça, principal investigator at the Instituto de Medicina Molecular João Lobo Antunes (iMM; Portugal) and Professor at the Faculty of Medicine of the University of Lisbon (FMUL) used lymph nodes, tonsils and blood to show how the cells that control production of antibodies are formed and act. The results, published in Science Immunology, unveil key aspects about the regulation of antibody production, with significant importance for diseases where antibody production is dysregulated such as autoimmune diseases or allergies.