Vitamin A deficiency decreases natural killer cell activity and interferon production in rats.
We examined the effect of vitamin A deficiency on natural killer (NK) cell activity and interferon (IFN) production. Rats were weaned at 16 or 21 d of age onto semisynthetic diets containing either 0 or 4 micrograms retinol/g diet. At the time of study, retinol-depleted rats had serum vitamin A concentrations less than 7% of those of pair-fed controls. In two studies, rats exhibited no external signs of retinol deficiency, but with further depletion some symptoms were observed. Splenic NK cell activity against chromium-51-labeled YAC-1 cells was significantly decreased in vitamin A-depleted rats (22-80% of values for control rats, depending on the degree of retinol deficiency), regardless of the ratio of effector to target cells used. When vitamin A-depleted rats were repleted orally with retinol, NK cell activity was consistently normalized. To understand the possible mechanisms involved in decreasing NK cell activity, we investigated IFN production by concanavalin A-stimulated spleen cells from vitamin A-depleted, from repleted and from control animals. IFN titers were significantly decreased (22-33% of values for control rats) in supernatants of spleen cell cultures of the vitamin A-depleted rats. Repletion with vitamin A resulted in IFN activities ranging from 80 to 130% of controls. Adding alpha/beta IFN in vitro to the spleen cells of vitamin A-depleted animals increased their NK cell activity. The number of spleen cells reacting with a monoclonal antibody specific for rat NK cells was slightly lower in retinol-depleted rats, but not enough to account for the differences in NK cell and IFN activities. These data suggest that vitamin A deficiency affect the nonspecific arm of the immune system, possibly by altering the functional capacity of cells to produce lymphokines needed for the generation of an appropriate cytolytic response.
Bowman
T A
TA
Department of Microbiology and Immunology, Medical College of Pennsylvania, Philadelphia 19129.
Goonewardene
I M
IM
Pasatiempo
A M
AM
Ross
A C
AC
Taylor
C E
CE
D000818:Animals; D000954:Antigens, Surface / Q000276:immunology; D001835:Body Weight; D007372:Interferons / Q000096:biosynthesis*; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D011919:Rats, Inbred Strains; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D014802:Vitamin A Deficiency / Q000276:immunology*
D000954:Antigens, Surface; D007372:Interferons