A stimulating new role for rapamycin

Although marketed as an immunosuppressant, Wyeth's Rapamune sirolimus (rapamycin) may now also have utility as an immunostimulatory vaccine adjuvant that raises the number of protective memory CD8 T cells, according to findings by Emory University researchers.¹ Before moving the drug into an adjuvant setting for cancer and infectious disease vaccines, the key will be finding a dose that turns on the CD8 T cells without dampening the activity of other types of T cells.

Rapamune, an inhibitor of mammalian target of rapamycin (mTOR; FRAP; RAFT1), is marketed to prevent renal transplant rejection. The drug's immunosuppressive mechanism likely involves blocking the proliferation of CD4 T cells and the maturation of dendritic cellswithout hampering the activity of regulatory T (T_reg) cells.²...