P-glycoprotein (encoded by multidrug resistance genes) is not required for interleukin-2 secretion in mice and humans.

P-glycoprotein (encoded by multidrug resistance genes), a member of the ATP-binding cassette transporter protein superfamily, has been shown to play a role in the secretion of cytokines. This conclusion was based upon the inhibition of cytokine secretion by anti-P-gp monoclonal antibodies. In this study, we show that anti-CD3-stimulated lymphocytes from wild-type, mdr1a knock out and mdr1ab double knock out mice produce similar amounts of IL-2, IFN-gamma, IL-4, and IL-10. In addition, Jurkat T cells that lack P-gp and MDR1-transfected Jurkat T cells (JurkatP-gp) as well as purified human peripheral blood CD4+ P-gp+ and CD4+ P-gp- and CD8+ P-gp+ and CD8+ P-gp- T cell subsets produced comparable amounts of IL-2. These data show that P-gp is not required for secretion of IL-2, IFN-gamma, IL-4, and IL-10 secretion in mice and IL-2 secretion in humans.