IL-7 is a cytokine that acts as a growth factor for early lymphoid cells of both B- and T-cell lineages. IL-9 is a multifunctional cytokine that, although originally described as a T-cell growth factor, its function in T-cell response remains unclear.
This entry represents interleukin-7 (IL7), it is a hematopoietic growth factor produced by bone marrow stromal cells. It promotes growth of B- and T-cell precursors and functions with IL2 in the activation of mature T-cells [ (PUBMED:2643102) (PUBMED:3259677) ]. IL-7 and IL-7Ralpha bind the gamma-c receptor forming a complex required for the development and homeostasis of T and B cells [ (PUBMED:19141282) ]. Interleukin-7 and Interleukin-9 belong to the same larger family.
Interleukin 9 and its receptor: an overview of structure and function.
Int Rev Immunol. 1998; 16: 345-64
Display abstract
Interleukin-9 (IL-9) is a multifunctional cytokine produced by activated TH2 clones in vitro and during TH2-like T cell responses in vivo. Although IL-9 was initially described as a T cell growth factor, its role in T cell responses is still unclear. While freshly isolated normal T cells do not respond to IL-9, this cytokine induces the proliferation of murine T cell lymphomas in vitro, and in vivo overexpression of IL-9 results in the development of thymic lymphomas. In the human, the existence of an IL-9 mediated autocrine loop has been suggested for some malignancies such as Hodgkin's disease. Various observations indicate that IL-9 is actively involved in mast cells responses by inducing the proliferation and differentiation of these cells. Other potential biological targets for IL-9 include B lymphocytes, and hematopoietic progenitors, for which higher responses were observed with foetal or transformed cells as compared to normal adult progenitors. The IL-9 receptor is a member of the hemopoietin receptor superfamily and interacts with the gamma chain of the IL-2 receptor for signaling. Signal transduction studies have stressed the role of the Jak-STAT pathway in various IL-9 bioactivities, whereas the 4PS/IRS2 adaptor protein might also play a significant role in IL-9 signaling.
This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with IL7 domain which could be assigned to a KEGG orthologous group, and not all proteins containing IL7 domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.
