Mediatophore regulates acetylcholine release from T cells.

Immunological stimulation of T cells by phytohemagglutinin (PHA) enhances the synthesis and release of acetylcholine (ACh), suggesting a role for the lymphocytic cholinergic system in the regulation of immune function. In the present study, we used two human leukemic T cell lines as models to investigate whether mediatophore, a homooligomer of a 16-kDa subunit homologous to the proteolipid subunit c of vacuolar H(+)-ATPase (V-ATPase), is involved in mediating ACh release from T cells. Immunohistochemical analysis revealed the presence of mediatophore in the cytoplasm and on the plasma membrane of both T cell lines. Mediatophore gene expression was up-regulated by immunological T cell activation by PHA. Transfection of anti-mediatophore small interference RNA down-regulated mediatophore gene expression and significantly reduced ACh release. These results suggest that T cells express mediatophore, which then plays a key role in mediating ACh release, and that mediatophore expression is regulated by immunological stimulation.