EBI3 is a 229 amino acid cytokine belonging to the type I cytokine receptor family (type 3 subfamily) with a signal peptide, 2 potential N-linked glycosylation sites, an LSDWS motif, 2 fibronectin type-III domains. It is usually induced due to infection of B lymphocytes by Epstein-Barr virus and due to expression of an EBV encoded latent membrane protein. EBI3 is a subunit of two heterodimeric cytokines interleukin-27 (IL27) and IL35. It is a secreted glycoprotein associated with calnexin and is a heterodimer with an alpha and a beta subunit. It is also known to interact with SQSTM1 and is responsible for the rapid clonal expansion of naive but not memory CD4 (+) T-cells. It strongly synergizes with IL-12 and trigger IFN-gamma production of naive CD4 (+) T-cells. It mediates its biologic effects through the cytokine receptor WSX-1/TCCR. It triggers signaling in T cells, B cells, and myeloid cells and along with p35 it acts as an important immunomodulator. It is usually expressed in various hemopoietic tissues and cell lines.Synonyms: EBV-induced gene 3 protein, Epstein-Barr virus-induced gene 3 protein, IL-27 subunit beta, IL-27B, Interleukin-27 subunit beta