IL-15 STIMULATES THE EXPANSION OF AIDS VIRUS-SPECIFIC CTL

It has been assumed that the maturation of pre-CTL to virus-specific e ffector CTL is dependent upon IL-2-mediated T cell triggering through the IL-2R, In view of its similarity to IL-2 in its effects on immune cells, we sought to determine whether IL-15 can induce the expansion o f AIDS virus-specific pre-CTL to mature CTL, PBL of SIVmac-infected rh esus monkeys or HIV-1-infected humans have previously been shown to ex pand to effector CTL when cultivated with a predicted CTL epitope pept ide and rIL-2, We now demonstrate that rIL-15 facilitates this expansi on of effector CTL. In fact, rIL-15-driven expansion of virus-specific CTL occurs in the presence of IL-2-neutralizing or anti-IL-2R Abs, in dicating that this cellular maturation can occur in an IL-2-independen t fashion, These studies suggest a mechanism by which CTL may be capab le of expanding in vivo in the absence of IL-2 and functional CD4(+) T lymphocytes.