EYRAplex: Human Th1/Th2 (7‑plex)

Interferon-γ (IFN-γ) is the only type II interferon. This proinflammatory cytokine is secreted by activated T cells and NK cells. It activates macrophages and endothelial cells and regulates immune responses by affecting APCs, T cells, and B cells. Production of IFN-γ by helper T cells and cytotoxic T cells is a hallmark of the Th1-type phenotype. Thus, high-level production of IFN-γ is typically associated with effective host defense against intracellular pathogens.

Interleukin 2 (IL-2) is predominantly produced by activated T cells. IL-2 promotes the proliferation, differentiation, and survival of antigen-activated T cells and NK cells. After antigen stimulation, the cytokine also promotes the differentiation of T cells into effector and memory T cells. Therefore IL-2 plays an important role in the body's response to infection. IL-2 is also key to tolerance, as it promotes the differentiation of certain immature T cells into regulatory T cells in the thymus, ultimately preventing autoimmune diseases. 

Interleukin 4 (IL-4) is produced primarily by Th2 cells, mast cells, eosinophils, and basophils. IL-4 was first identified to costimulate B cell growth; the cytokine is essential for B cell secretion of IgE and augments the production of IgG1 in vivo. In addition to regulating B cell growth and immunoglobulin secretion, IL-4 also affects T cells. In vitro, IL-4 promotes T cell growth and can induce cytolytic T cell activity. IL-4 also induces the differentiation of naive CD4 T cells into Th2 cells, which are characterized by their capacity to secrete the cytokines IL-4, IL-5, and IL-10 upon activation, while simultaneously inhibiting the generation of Th1 cells.

Interleukin 5 (IL-5) is a pleiotropic cytokine primarily produced by T and NK cells.  IL-5 specifically controls the survival, differentiation, and chemotaxis of eosinophils. But initially, IL-5 was characterized by its ability to support the growth and terminal differentiation of B cells.

Interleukin 6 (IL-6) is a pleiotropic cytokine produced by many different cell types and plays a role in a wide range of functions, such as immune responses, acute-phase reactions, and hematopoiesis. Among other things, it augments antibody production from activated B cells in vitro.

Interleukin 12 (IL-12) is, when biologically active, a heterodimer (p70) consisting of two covalently linked subunits, p35 and p40. The p40 subunit is shared with IL-23. IL-12 is produced by antigen-presenting cells, specifically dendritic cells, and macrophages. IL-12 is a proinflammatory cytokine that promotes Th1-type responses by inducing IFN-γ production and enhancing the proliferation and cytotoxicity of NK and T cells.

Tumor necrosis factor (TNF), also known as TNF-α, is produced by many different cell types, e.g., monocytes, macrophages, T cells, and B cells. Among the many effects of TNF-α are protection against bacterial infection, cell growth modulation, immune system regulation, and involvement in septic shock.