Figure 3.

B-cell development in interaction space. The evolution of the system of antibodies can be interpreted as clones filling the interaction space at various levels of resolution. Along this pathway, cells continually increase their BCR affinity towards the target. Beyond the mean energy of the system, represented by red circle, TD responses allow further directed differentiation via somatic hypermutations in germinal centers. Clonal expansions are however followed by retraction, effector cells eliminated by apoptosis and only memory B cells and plasma cells surviving. Different colors stand for structural differences and relationships. LLPC, long-lived plasma cell; MBC, memory B cell; immat, immature B cell.