4.3.1 Effect of rapamycin on immunity
The encouraging anti-aging effects of rapamycin in animal studies have
spurred a great interest in translating these results to human.
Intriguingly, rapamycin at a high dose is known to suppress the immune
system, which is why it has been used as an immunosuppressant in organ
transplantation. However, when tweaking rapamycin to a lower dosage,
rapamycin appears to stimulate immunity. In 2014, a milestone study on
the immunity-boosting effect of rapamycin was reported by researchers at
Novartis 154. In a double-blind randomized study, they
administered everolimus, a derivative of rapamycin, to 218 healthy
subjects aged 65 and older for 6 weeks and then stopped the use for 2
weeks before giving them a flu shot. A twenty percent increase of immune
response was observed in the everolimus-receiving group, indicating that
rapamycin and its analogs (rapalogs) may boost immunity in humans.
Furthermore, to minimize the adverse effects of rapamycin, a combination
of rapamycin and rapalogs have been subsequently explored. A low dose of
rapalogs combined with catalysts have been shown to induce a 40%
infection reduction in the healthy elderly (aged 65 and older) subjects
who received the rapamycin treatment before flu shot —and more
importantly, this combination of therapy was suggested to be
well-tolerated in the majority of the subjects 155.