Stages in development B cells
• Phase 1: B cell precursors in bone marrow acquire
functional antigen receptors via gene rearrangements
• Phase 2: elimination anti-self (tolerance) in bone
marrow and 2nd lymphoid tissues
• Phase 3: positive selection for B cells expression of
pathogen specific Ig in 2nd lymphoid tissues
• Phase 4: mature B cells circulate via lymph and blood
to lymphoid tissues patrolling for infections
• Phase 5: proliferation and clonal expansion pathogen
specific B-cells in 2nd lymphoid tissues
• Phase 6: maturation into:
• plasma cells =>remain in 2nd lymphoid tissues, express large quantities
pathogen specific Ab
• memory B cells (circulate) for rapid Ab generation in case of future
infections with same pathogen