Modulation of interleukin 2 activity by delta 9-tetrahydrocannabinol after stimulation with concanavalin A, phytohemagglutinin, or anti-CD3 antibody.

The effects of delta 9-tetrahydrocannabinol (THC) on lymphocyte proliferation and interleukin (IL) 2 activity was investigated using adult murine spleen cells stimulated with either the mitogens concanavalin A, phytohemagglutinin, or anti-CD3 antibody. THC was found to suppress mitogen-induced proliferation, but to enhance anti-CD3-antibody-induced proliferation. These results reflected THC-induced suppression of Ly2 cells following concanavalin A or phytohemagglutinin stimulation and THC-induced enhancement of Ly2 cells following CD3 stimulation. The combination of THC and concanavalin A or phytohemagglutinin resulted in suppressed IL-2 activity, whereas the combination of THC and anti-CD3 antibody resulted in enhanced IL-2 activity. This drug-related modulation of IL-2 activity corresponded to the changes in blastogenic activity as well as to variations in numbers of Tac positive cells. These results suggest that the dysregulation in immune responses following THC treatment, either suppression or enhancement, may relate to the effects of THC on IL-2 production.