The effects of cannabinoids and cannabispiro compounds on Escherichia coli adhesion to tissue culture cells and on leukocyte functions in vitro.

delta 9-Tetrahydrocannabinol, cannabidiol, cannabidiolic acid, tetrahydrocannabidiolic acid, cannabispirol, acetylcannabispirol, cannabispirone, and cannabispirenone in a low concentration did not affect the adhesion of Escherichia coli on cultured HEp-2 cells. Cannabinoids at 10(-6) M increased the chemiluminescence of human polymorphonuclear leukocytes, while the cannabispiro compounds failed to enhance the oxidative burst of leukocytes. In lymphocyte and granulocyte function tests (E- and EA-rosette formation, blast transformation of T-lymphocytes in the presence of phytohaemagglutinin and concanavalin-A, ADCC and phagocytosis) all compounds displayed immunosuppressive effect at 1.5 X 10(-5) M. Tetrahydrocannabidiolic acid exerted the weakest immunosuppression on human leukocyte functions.