Since older individuals are less ab

Since older individuals are less able to generate effective immune responses to vaccination, one might speculate that RAPA would further compromise the antibody response to standard vaccines (like those for seasonal flu). However, data from murine models suggest the opposite. Specifically, young and old C57BL/6 mice were fed a diet containing either encapsulated rapamycin or a control diet (capsular material lacking RAPA) for seven months. The mice were then challenged subcutaneously with an inoculum containing Aggregatibacter actinomycetemcomitans, a human periodontal pathogen that does not naturally infect mice. The antibody response to bacterial challenge was enhanced significantly by RAPA in older animals, 28 months of age at challenge. No RAPA enhancement was seen in adult mice. These data (Benavides and Kraig, in preparation), suggest that RAPA may have different immune outcomes when tested in old vs. young subjects.