Activated NK-92 cells regulate the expression of proteins associated with apoptosis. (A) Representative western blots comparing the expression of Bax and Bcl-2 in addition to JAK2 and STAT1 phosphorylation in control, IL-2 and IL-2 + pAb IL-15 groups. Compared with the control group, IL-2 stimulation significantly (B) increased BAX expression, (C) reduced Bcl-2 expression, and reduced the ratios of (D) p-JAK2/JAK2 and (E) p-STAT3/STAT3. All of the aforementioned effects were reversed when pAb IL-15 was co-administered with IL-2. **P<0.01. NS, not significant; IL, interleukin; JAK2, Janus kinase 2; p-JAK2, phosphorylated JAK2; p-STAT3, phosphorylated STAT3; pAb, polyclonal antibody.