Abstract
The effects of nutritional supplements on immunity are still not well understood. For example, although aging affects immune cell responsiveness, it is not well known if immune stimulation by some nutritional supplements is also affected by aging. We have previously shown that the ellagitannin oenothein B and Acai berry polysaccharides (AcaiPS) enhance IFNγ production by both bovine and human NK cells and T cells. We wanted to examine the effect age had on this activity. Studies comparing immune responses in immature individuals to those in adults are difficult to perform in humans and mice. As such, we utilized the bovine system to examine the responsiveness of T cells and NK cells from newborn calves, older calves, and adult cows to oenothein B and AcaiPS in vitro. Oenothein B induced greater IFNγ production by T cells from adults compared to calves. Within the responsive T cell population, we found that CD45RO+ T cells expressed more IFNγ in response to oenothein B than CD45RO- T cells. Similar responses were seen in a limited analysis with human cells. In contrast, AcaiPS, both alone and in combination with IL-18, induced greater IFNγ production by NK cells from calves, especially newborn calves, compared to adults. Our data suggest that immune stimulation of T cells and NK cells by oenothein B and AcaiPS is influenced by age. It also suggests that the bovine model may be very useful in examining the effect of age on immune stimulation by nutritional supplements.
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