Protective antibody-mediated immune responses typically depend on the generation of high-affinity antibodies with the capacity to neutralize pathogen activity and trigger effector functions of innate immune cells. Yet, antibody functions can be harmful in autoimmune diseases and allergic reactions. Thus, understanding how antibodies are generated is fundamental for the design of vaccination strategies and for the manipulation of B cell responses in these pathological conditions. The generation of most long-lived antibodies depends on collaboration between cognate T cells and B cells that interact with each other and exchange signals that promote B cell clonal expansion and differentiation into antibody-secreting cells, germinal center B cells and memory B cells. The current meeting will focus on the cellular dynamics of B-T cell interactions and the underlining molecular mechanisms that promote the differentiation of B cells both within and independent of germinal centers. Similar events that occur in non-lymphoid organs such as in mucosal tissues and tumors will be addressed as well. In addition, T-B collaborations that drive pathological conditions such as in autoimmunity, allergy, and their positive functions in cancer will be discussed. This meeting will be held in conjunction with the 'B cells and Plasma Cells in Health and Disease' meeting.