ELISAs For Quantifying Cytokine Release

Cytokines are a broad group of soluble and transient bioactive proteins that range in size from 6 to 70 kilodaltons (kDa) (1). These pleiotropic and redundant (2) proteins act via autocrine, paracrine, and endocrine signaling mechanisms to produce effects that can be additive, antagonistic or synergistic. Cytokines are secreted by immune cells such as neutrophils, monocytes, macrophages, B cells and T cells to modulate immune responses (1). Cytokines are very bioactive, and as such, circulating levels are typically low in healthy people.  Immunotherapy or viral infections can stimulate excessive cytokine secretion or even cytokine release syndrome (CRS). Also known as the cytokine storm, CRS is a systemic inflammatory response that has symptoms ranging from mild fever to death. Given the broad range of cytokine effects, a great deal of effort is aimed at quantifying secretion as part of an immunotherapy or viral infection workflow. Although a wide variety of assays are available for measuring cytokines, enzyme linked immunosorbent assays (ELISAs) are one of the most commonly used tools in cytokine research and development.