Answer to Question #236862 in Biology for Siyabonga

Question

Trace the development of B cells,T cells and macrophages from the common stem cell

Answer 1

Both B cells and T cells are lymphocytes that are derived from specific types of stem cells, called multipotent hematopoietic stem cells, in the bone marrow. After they are made in the bone marrow, they need to mature and become activated. Each type of cell follows different paths to their final, mature forms.

B cells. After formation and maturation in the bone marrow (hence the name “B cell”), the naive B cells move into the lymphatic system to circulate throughout the body. In the lymphatic system, naive B cells encounter an antigen, which starts the maturation process for the B cell. B cells each have one of millions of distinctive surface antigen-specific receptors that are inherent to the organism’s DNA. For example, naive B cells express antibodies on their cell surface, which can also be called membrane-bound antibodies.

T cells. Once formed in the bone marrow, T progenitor cells migrate to the thymus (hence the name “T cell”) to mature and become T cells. While in the thymus, the developing T cells start to express T cell receptors (TCRs) and other receptors called CD4 and CD8 receptors. All T cells express T cell receptors, and either CD4 or CD8, not both. So, some T cells will express CD4, and others will express CD8.