**5.2 Roles of selenium in the immune response**

The lymph nodes and the liver contain high amount of selenium which helps to brace up the formation of antibodies and increase the functioning of the helper T cells and cytotoxic NK cells. It also stimulates the migration of the phagocytic cells [8, 45]. Metabolites of selenium such as GPx-1 and thioredoxin reductase have also been implicated in the inflammatory and immune responses although the mode of action is not fully known [46, 47]. Deficiency of selenium in the endothelial cells reduced the production of prostaglandins. In addition, it was reported that dairy cows deficient in selenium had low production of blood neutrophils hence their ability to kill a pathogen was nullified [47]. A rapid production and differentiation of CD4+ and T cells were observed in subjects who ingested selenium leading to increased poliovirus clearance [48].
