AP BIOLOGY

Detailed explanation-1: -B lymphocytes originate in the bone marrow; their goal is to recognize an antigen.

Detailed explanation-2: -Bone marrow is major organ for the development and maturation of B cells. B cells are generated from HSCs and developed in bone marrow before they egress into peripheral blood to reach peripheral lymphoid organs. Specific cellular niches for B-cell development include CXCL12-expressing cells and IL-7-expressing cells.

Detailed explanation-3: -B cells are generated in the bone marrow after a transient phase of production in fetal liver and, to a lesser extent, in other embryonic tissues (1–5).

Detailed explanation-4: -B cells. These are a type of white blood cell involved in humoral immunity. They make up around 20% of white blood cells. B cells originate and mature in the red bone marrow, then after release they concentrate in the lymph nodes, respiratory tract, gastrointestinal tract, and spleen, ready for pathogenic invaders.

Detailed explanation-5: -After leaving the bone marrow, the cell starts to produce cell-surface IgD molecules as well, with the same antigen-binding site as the IgM molecules. It is now called a mature naïve B cell. It is this cell that can respond to foreign antigen in peripheral lymphoid organs (Figure 24-22).