B cells mature primarily in two locations:
- Bone marrow: B cells originate and begin their maturation in the bone marrow, where hematopoietic stem cells differentiate into immature B cells. This stage includes gene rearrangements for the B cell receptor and selection processes to eliminate self-reactive cells
- Spleen: After leaving the bone marrow as immature or transitional B cells, they migrate to the spleen for further maturation. In the spleen, transitional B cells progress through stages (T1 and T2) and differentiate into mature B cell subsets such as follicular B cells or marginal zone B cells, completing their maturation
Thus, B cell maturation is a multi-step process starting in the bone marrow and finishing in peripheral lymphoid organs like the spleen.
