IL-17B is a disulfide-linked homodimer T cell-derived cytokine that belongs to the IL-17 family of structurally-related cytokines. They share a highly conserved C-terminal region but differ from one another in their N-terminal regions and in their distinct biological roles. This cytokine was reported to stimulate the release of TNF-α and IL-1β from a monocytic cell line. IL-17B is primarily localized to neuronal cell bodies. Numerous immune regulatory functions have been reported for the IL-17 family of cytokines, presumably due to their induction of many signaling molecules. The most notable role of IL-17 is its involvement in inducing and mediating proinflammatory responses. IL-17 is commonly associated with allergic responses. IL-17 induces the production of many other cytokines, such as IL-6, G-CSF, GM-CSF, IL-1β, TGF-β, TNF-α; chemokines including IL-8, GRO-α, and MCP-1; and prostaglandins from many cell types (fibroblasts, endothelial cells, epithelial cells, keratinocytes, and macrophages). The release of cytokines mediates several functions, such as airway remodeling, a characteristic of IL-17 responses. The increased expression of chemokines attracts other cells, including neutrophils but not eosinophils. IL-17 function is also essential to a subset of CD4+ T cells called Th17 cells. As a result of these roles, the IL-17 family has been linked to many immune/autoimmune related diseases including rheumatoid arthritis, asthma, lupus, allograft rejection, anti-tumor immunity and recently Psoriasis. The six known members of this family, IL-17A through IL-17F, are secreted as homodimers. IL-17A and IL-17F can associate to form IL-17A/F heterodimer. IL-17B is expressed by T cells and has been shown to stimulate release of TNF-α and IL-1β from cells of monocyte lineage.