Alterations in murine delayed type hypersensitivity responses by delta-8-THC and cannabinol.

The ability of cannabinol and delta-8-tetrahydrocannabinol (delta-8-THC), two cannabinoid marihuana components, to modify delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) was investigated in mice. Reduction of DTH reactivity by cannabinol required multiple, daily, postimmunization drug administration. Neither multiple preimmunization dosings nor a single postimmunization dosing was effective. Delta-8-THC produced moderate (13-33%) suppression of DTH reactivity only upon multiple, preimmunization treatments, whereas postimmunization administration only delayed peak DTH reactivity 24 hours without altering the absolute response level. These results indicate that delta-8-THC and cannabinol possess slight to moderate activity in the suppression of DTH.