IMMUNOLOGY

Detailed explanation-1: -B cell activation occurs in the secondary lymphoid organs (SLOs), such as the spleen and lymph nodes. After B cells mature in the bone marrow, they migrate through the blood to SLOs, which receive a constant supply of antigen through circulating lymph.

Detailed explanation-2: -B cell development starts in the bone marrow (BM) and continues in the spleen to final maturation. Developmental progression is guided by sequential events leading to assembly, expression, and signaling of the B cell antigen receptor (BCR).

Detailed explanation-3: -B-cell production in humans is a lifelong process that starts in the fetal liver intrauterine and bone marrow after birth. Their development is from hematopoietic stem cells.

Detailed explanation-4: -Both B and T lymphocytes originate in the bone marrow but only B lymphocytes mature there; T lymphocytes migrate to the thymus to undergo their maturation. Thus B lymphocytes are so-called because they are bone marrow derived, and T lymphocytes because they are thymus derived.

Detailed explanation-5: -Newly formed B cells in the bone marrow are sensitive to antigen receptor cross-linking, a characteristic that favors elimination of self-reactive B-cell clones (7). B cells that escape this negative selection migrate to the peripheral lymphoid tissues.