Interleukin-12 subunit alpha is a protein  expressed by activated dendritic cells (DC), macrophages, and monocytes and plays an important role in sustaining IFN production and the generation  and encoded by the IL12A gene which encodes a subunit of the cytokine Interleukin 12 (IL-12) that acts on T and natural killer cells and  is required for the T-cell-dependent induction of interferon gamma .
Interleukin-12 subunit alpha (IL-12 p35) is a protein that in humans is encoded by the IL12A gene. This gene encodes a subunit of the cytokine Interleukin 12 (IL-12) that acts on T and natural killer cells, and has a broad array of biological activities. This cytokine is required for the T-cell-dependent induction of interferon gamma (INF-), and is important for the differentiation of both Th1 and Th2 cells. 
