DIFFERENT REGULATORY EFFECTS OF PENTOXIFYLLINE ON HUMAN T-CELL ACTIVATION PATHWAYS

Pentoxifylline (PTX), a methylxanthine derivative, was examined for it s effects on T cell proliferation and cytokine production stimulated b y cross-linking anti-CD3 alone, anti-CD3 with PMA, anti-CD3 with anti- CD26, or anti-CDS with anti-CD28 mAb, respectively. PTX at a 3.5 x 10( -5) M concentration significantly inhibited T cell proliferation and t he production of tumor necrosis factor-alpha, interleukin-2, and inter leukin-4. Moreover, this effect was selective for stimulation by cross -linking anti-CD3 with PMA, or anti-CD3 with anti-CD26, but not by cro ss-linking anti-CDS with anti-CD28. These results suggest that the inh ibitory effect of PTX on T cell activation involves the CD3 and CD26, but not the CD28 signal pathway.