PATHOLOGY

Detailed explanation-1: -T lymphocytes develop from a common lymphoid progenitor in the bone marrow that also gives rise to B lymphocytes, but those progeny destined to give rise to T cells leave the bone marrow and migrate to the thymus (see Fig. 7.2). This is the reason they are called thymus-dependent (T) lymphocytes or T cells.

Detailed explanation-2: -B-cells and T-cells are the two main types of lymphocytes. There are primary and secondary organs involved in the complex development of lymphocytes, but in most cases, B-and T-lymphocytes are generated in bone marrow and in the thymus.

Detailed explanation-3: -They develop from hematopoietic stem cells, which are produced in our bone marrow.

Detailed explanation-4: -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-5: -Both B and T cells originate in the bone marrow. These cells are involved in adaptive immunity. They are a type of lymphocytes.