Enzyme ImmunoAssay (EIA) is a technique to detect and quantify antigens (proteins, hormones…) or antibodies in samples. It relies on the ability of an antibody to bind a specific antigen. Either the antibody or the antigen is labelled with an enzyme whose substrate is a chromogen or a fluorogen converted in a measurable product (color or fluorescence).|Enzyme-linked Immunosorbent Assay (ELISA) is a type of EIA using a solid phase (ex: microtiter plate) coated with an antigen immobilizing the molecule to detect. Over the time, scientists have extended the term ELISA to EIAs using an antibody coating the solid phase. That explains why our EIA kits using coated antibodies are also called ELISA kits.|Discovered in 1992, Interleukin-4 (IL-4) is a monomeric glycosylated polypeptide with a molecular weight of 18-20 kDa. IL-4 structure contains four alpha-helices which are anti-parallel and two anti-parallel beta-sheets.|IL-4 is also known as B-cell stimulatory factor 1 or B-cell growth factor 1 and as Lymphocyte stimulatory factor. IL-4 is a key regulator in humoral and adaptive immunity. IL-4 plays an essential role by promoting Th2 cell differentiation while inhibiting Th1 cell differentiation. IL-4 is an anti-apoptosis factor for the immune and non-immune cells. Due to its main function, IL-4 is an anti-inflammatory cytokine in autoimmune diseases. IL-4 deregulation could be a factor in the development of some diseases like allergic diseases or in the treatment resistance of tumors
