Chapter 26.4, Problem 1CR

Leukocytes are differentiated white blood cells derived from either myeloid or lymphoid precursor cells. Cells of myeloid lineage include monocytes and granulocytes. Monocytes include macrophages and dendritic cells, specialized phagocytes that function as antigen-presenting cells (APCs) to initiate an adaptive immune response. Granulocytes include neutrophils, which are also phagocytes but not APCs, and mast cells, which are important inducers of the inflammatory response but may also cause allergic reactions. Lymphocytes include B and T cells, which facilitate adaptive immunity, and natural killer cells, which play a key role in destroying virus-infected and cancerous host cells.

What is the origin of the phagocytes and lymphocytes active in the immune response? Track the maturation of B cells and T cells.