Cytokines in the beginning stages of the immune response

Cytokine regulate the innate as well as adaptive immunity. The creation a particular cytokine environment by antigen presenting cells, mainly dendritic cells and macrophages is critical for the determination of the appropriate type of adaptive immune response mediated by lymphocytes T. The differentiation and proliferation of lymphocytes depend on the set of cytokines present in the region of inflammation. The differentiation of lymphocytes into Th1 depend upon IFN-g, IL-12 and IL-18. When in high concentrations IL-1b and IL-23 are present, the lymphocytes differentiate to Th17. Several autoimmune conditions as rheumatoid arthritis, have been shown to involve Th17 cells. The differentiation into Th2 depend upon IL-4, IL-10, and IL-13, while the secretion of IL-4, IL-5, IL-6, IL-10, IL-13 and GM-CSF by Th2 cells in cooperation with IL-2 lead to the stimulation of humoral immunity by helping B cell activation. The activation of B lymphocytes by autoantigen specific Th2 can lead to the autoimmune reaction. The regulatory, Treg cells, which inhibit immune response are generated in the presence of TGF-b.