Stimulation of cell-mediated resistance in mice to infection with Listeria monocytogenes by vitamin A.

Vitamin A given as retinol-acetate, retinol-palmitate as well as the derivates retinoic acid and a retinoid, strongly fortified the resistance of mice to infection with virulent cells of Listeria monocytogenes. However, strong enhancement of resistance was only achieved when high toxic doses of vitamin A were given. Apparently, this effect was due to a stimulation of the function of the mononuclear phagocytic system rather than of the T lymphocyte.