Serum Proteins Affect the Inhibition by Delta-Tetrahydrocannabinol of Tumor Necrosis Factor Alpha Production by Mouse Macrophages

Abstract

In vitro studies of the effects of marijuana’s major psychoactive component, delta-9-tetrahydrocannabinol (THC), on immune functions show that THC is able to inhibit a variety of immune functions (1,2). However, the effect of THC on tumor necrosis factor (TNF) production by macrophages has not been reported until recent work in our laboratory (3). TNF-α, which is secreted principally by activated macrophages (4), has recently been shown to be produced in greater amounts if stimulation of murine peritoneal macrophages is performed in medium containing Salmonella enteritidis lipopolysaccharide (LPS) and 0.5% bovine serum albumin (BSA) in place of 10% fetal bovine serum (FBS) (Z. M. Zheng & S. Specter, unpublished observations). The use of BSA resulted in a reduction in the serum protein in the medium used to examine the effect of THC on TNF-α production (3). This reduction of serum is important since increasing the serum concentration in culture medium has been shown to inhibit in vitro activity of THC (5). In the current report, we present the effect of FBS and BSA on the inhibition by THC of TNF-α production by mouse resident peritoneal macrophages.