Taken together, these findings showed that FmIL-15 is expressed and secreted by murine tumor cells upon infection with FmIL-15-encoding oncolytic measles vectors and that this secreted form of the IL-15/IL-15R complex is functional, promoting lymphocyte survival and proliferation, activation of JAK/STAT signaling, and expression of downstream IL-15 target genes. Here, IL15 is linked to infection.