Although the combined mice (n = 7) of this experiment and a repeat that had been treated with IL-15 and T cell-depleted succumbed to the infection, the time to death was prolonged (median 14 days) compared to a median of 8 days for T-cell depleted mice that did not receive IL-15 (p<0.0001, Mantel Cox) (Fig 3C). This evidence concerns the gene IL15 and infection.