Which cytokine is a crucial growth factor for B cells and T cells and is produced by stromal cells in bone marrow and thymus?

Interleukin 7 (IL-7) plays a critical role as a growth factor for both B cells and T cells, supporting their development and survival. This cytokine is primarily produced by stromal cells located in the bone marrow and thymus, which are essential sites for hematopoiesis and lymphocyte maturation.

IL-7 acts on precursor cells, helping to initiate the process of lymphocyte differentiation and proliferation. In the bone marrow, it is important for the development of B cells from common lymphoid progenitors. Similarly, in the thymus, IL-7 is essential for the proliferation and maturation of T cell precursors. The interaction of IL-7 with its receptor on these cells is crucial for maintaining their viability and advancing through various stages of development.

Other cytokines mentioned, such as Interleukin 6, Interleukin 2, and Interleukin 3, have different roles in the immune response and hematopoiesis. For instance, IL-6 is primarily involved in inflammatory responses and is important for B cell differentiation into antibody-secreting plasma cells, but it is not specifically a growth factor for T and B cell development like IL-7. Interleukin 2 is mainly produced by