STAT5 and ERK1/2 signaling pathways are activated by IL-15 in SD-1 cells. (A) SD-1 cells were treated with IL-15 (25 ng/mL) for 15, 30, 45, 60, or 120 minutes. Cell lysates were analyzed by western blot using antibodies as indicated. (B) Western blot band density was analyzed via ImageJ software (National Institutes of Health) and adjusted densitometry values for phosphorylated STAT5 (pSTAT5) calculated by dividing the relative densities for pSTAT5 by the relative densities for total STAT5. (C-D) Adjusted densities values for (C) phosphorylated ERK1/2 (pERK1/2) and (D) phosphorylated IκBα (pIκBα) were calculated in a manner similar to above, except that relative densities for total ERK1/2 and IκBα were used, respectively.