An increase in activity of natural killer cells in rats with vitamin A deficiency

: A study was made of the effect of different supply of rats with vitamin A on the membranotoxic activity of natural killers, which was assessed with the use of target cells K-562 labeled with 3H-uridine incubated jointly with splenocytes. The animals were kept on a semi-synthetic diet deprived of vitamin A. This led to a reduction of the body weight and retinol content in the liver. At the same time the membranotoxic activity of splenocytes rose 1.5-fold as compared with controls kept on a balanced diet. Administration of retinol palmitate to the animals with vitamin A deficiency suppressed the activity of natural killers, raising the retinol content in the liver. The intensity of the effects in question depended on the ratio of the effector cells and targets. The possible mechanisms of the potentiation of natural antitumor resistance in animals with vitamin A deficiency are under discussion.