IL-35 is a member of the IL-12 cytokine family. It is a heterodimeric protein composed of EBI-3 (Epstein-Barr virus-induced gene 3) and p35 (IL-12A) subunits. EBI-3 (IL-27B) is a 34 kD glycoprotein that is related to the p40 (IL-12B) subunit of IL-12. p35/IL-12A is a 35 kD glycoprotein that is related to the p19 (IL-23A) and p28 (IL-27A) subunits of IL-27 and IL-23, respectively. IL-35 is a new anti-inflammatory cytokine with many reported biological functions. One of the proposed functions of IL-35 is regulating T regulatory (Treg) cell. IL-35 is expressed by T regulatory cells. It expands CD4+CD25+ Treg cells, suppresses the proliferation of CD4+CD25- effector cells, and inhibits Th17 cell polarization. IL-35 also suppresses collagen-induced arthritis or Helicobacter-induced colitis in animal models. High levels of IL-35 were found in the plasma samples of acute myeloid leukemia patients and synovial fluid samples of patients with rheumatoid arthritis. However, relative levels of IL-35 in biological samples and its significance are not fully understood at the time of this kit release. LEGEND MAX(TM) Human IL-35 Heterodimer ELISA kit is a Sandwich Enzyme- Linked Immunosorbent Assay (ELISA) with a 96-well strip plate that is precoated with a capture antibody. This kit is specifically designed for the accurate quantitation of human IL-35 heterodimer from cell culture supernatant, serum, plasma and other biological fluids. This kit is analytically validated with readyto-use reagents.