Which term describes the site where T cells mature?

Which term describes the site where T cells mature?

• A. Lymph nodes
• B. Spleen
• C. Thymus
• D. Bone marrow

Answer: (C)

T cell maturation occurs in the thymus. In this organ, developing thymocytes undergo gene rearrangements for their T-cell receptors and go through positive selection to ensure they can recognize self-MHC molecules, and negative selection to weed out cells that would strongly react against self-antigens. This education step is what makes the thymus the primary site for T cell maturation before they enter the circulation and peripheral lymphoid tissues to respond to pathogens. Lymph nodes and the spleen are where mature T cells encounter antigens and coordinate responses, not where they finish maturing. Bone marrow is the site of hematopoiesis and is where lymphoid progenitors originate; T cells migrate to the thymus to complete maturation.

T cell maturation occurs in the thymus. In this organ, developing thymocytes undergo gene rearrangements for their T-cell receptors and go through positive selection to ensure they can recognize self-MHC molecules, and negative selection to weed out cells that would strongly react against self-antigens. This education step is what makes the thymus the primary site for T cell maturation before they enter the circulation and peripheral lymphoid tissues to respond to pathogens. Lymph nodes and the spleen are where mature T cells encounter antigens and coordinate responses, not where they finish maturing. Bone marrow is the site of hematopoiesis and is where lymphoid progenitors originate; T cells migrate to the thymus to complete maturation.