Interleukin 7 (IL-7) is a lymphoid cell growth factor that affects pre-B, pro-B, and early T cells. IL-7 was previously known as pre-B cell growth factor and lymphopoietin 1. IL-7 supports the growth of early B cells from long-term lymphoid bone marrow cultures. It is mitogenic to thymocytes and enhances the response of cells to other stimuli such as polyhydroxyalkanoate (PHA) and concanavalin A (ConA). IL-7 stimulates the proliferation of CD4+/CD8+ cells. The proliferative response of thymocytes to IL-7 is not affected by antibodies to the T cell growth factors such as IL2, IL4 and IL6, suggesting that IL-7 is capable of stimulating T cell proliferation through a pathway independent of the known T cell growth factors. Mature T cells respond to IL-7 and Con A, but not to IL-7 alone. In myeloid lineage cells, IL-7 upregulates the production of pro-inflammatory cytokines and stimulates the tumoricidal activity of monocytes/macrophages. IL-7 is expressed by adherent stromal cells from various tissues.

Secreted