Systemic administration of IL-15 augments T cell-directed vaccine responses.

2003 JAN 8 - (NewsRx.com & NewsRx.net) -- A study by researchers in the U.S. shows for the first time that interleukin-15 (IL-15) is capable of augmenting the primary CD8+ T-cell response to vaccination.

"The systemic administration of IL-2 can act as a potent adjuvant for T-cell-directed vaccine strategies. However, not only is the administration of IL-2 potentially toxic, but recent evidence suggests that it may also paradoxically limit the duration and magnitude of the cytotoxic T-cell response. A recently identified cytokine, IL-15, shares many properties with IL-2 and may provide a preferential means of augmenting T-cell-directed vaccine responses," stated M.P. Rubinstein and colleagues, Medical University of South Carolina.

"Although well characterized in vitro, there are few data on the ability of IL-15 to augment T-cell-mediated responses in vivo. We therefore evaluated the ability of systemic IL-15 to function as a T-cell adjuvant in a murine vaccine model," the researchers said.

"To establish a population of easily identifiable Ag [antigen]-responsive T cells, naive CD8+ (OT-1) T cells were first adoptively transferred into mice," explained Rubinstein and coworkers.

They reported that "[v]accination with peptide-pulsed dendritic cells induced a modest expansion of OT-1 T cells. The addition of systemic IL-15 for seven days following vaccination resulted in a significant increase in the expansion of responding T cells in the PBL, spleen, and lymph nodes."

...