Dr. A. Catharine Ross, who holds the Dorothy Foehr Huck Chair in Nutrition at Penn State, directed the study. She says, "there aren't very many examples of using nutrition to improve immune response. These results show that a natural product of vitamin A can have an important role in regulating immunity and, when administered along with PIC, a synthetic immunity booster, might be a potentially powerful nutritional-immunological assist in vaccination."
In previous studies, the Penn State researchers had shown that retinoic acid boosts the adult mouse response to the tetanus vaccine. In the current investigation, they studied the response in week-old mice. Mouse pups, like human infants, have a weaker response to vaccination than do adults due to the immaturity of their immune system.
The mice were given oral doses of retinoic acid along with a tetanus shot. The pups that received the retinoic acid developed a four times better immune response than mice that didn't receive the vitamin A product. Mice that received both retinoic acid and, PIC, the synthetic immunity booster polyriboinosinic: polyribocytidylic acid, developed a seven times higher immune response.
In addition, the researchers found that the combined retinoic acid/PIC treatment produced a more balanced enhancement than either retinoic acid or PIC alone.
Ross explains that the researchers measured three subtypes of tetanus antibodies in blood samples from the mouse pups after vaccination. Both retinoic acid and PIC, when administered alone, each increased the antibodies about four-fold over all but the combination retinoic acid/PIC treatment resulted in elevated levels that had proportions of antibody types most like untreated pups.
Ross explains that the human body makes retinoic acid from ingested vitamin A in very controlled amounts. Eating higher amounts of vitamin A doesn't automatically result in higher levels of retinoic acid in the body.
MEDICA.de; Source: Penn State