Marijuana immune function

Klein, T., Friedman, H, Modulation of murine immune cell function by marijuana components, in Drugs of Abuse and Immune Function, Watson, R. CRC Press, Boca Raton, FL, 1990, pp. 87-111. 

Researchers also have difficulty correlating a diminished immune function with THC exposure. Some found that the short-term immunosuppressive effects of THC were not well established. Others note that because heavy marijuana smokers can tend to have erratic lifestyles, they may increase their chances of infection or illness simply by lowering their immune function through poor sleep and nutrition. 

The effects of marijuana on immune function have been reviewed (122). The studies suggest that marijuana affects immune cell function of T and B lymphocytes, natural killer cells, and macrophages. In addition, cannabis appears to modulate host resistance, especially the secondary immune response to various infectious agents, both viral and bacterial. Lastly, marijuana may also affect the cytokine network, influencing the production and function of acute-phase and immune cytokines and modulating network cells, such as macrophages and T helper cells. Under some conditions, marijuana may be immunomodulatory and promote disease. 

Delta-9-THC is the main active constituent extracted from Cannabis sativa (Tuner, 1985 in Marijuana 1984, Ed. Harvey, DY, IRL Press, Oxford). Numerous articles have described not only psychotropic effects of cannabinoids but also their influence on the immune function [Hollister L. E., J. Psychoact. Drugs 24 (1992) 159-164]. The majority of in vitro studies have shown that cannabinoids have immunosuppressant effects inhibition of the mitogen induced proliferative responses of T lymphocytes and B lymphocytes [Luo, Y. D. et ah, Int. J. Immuno-pharmacol. (1992) 14,49-56 Schwartz, H. et at., J. Neuroimmunol. (1994) 55,107-115], inhibition of the activity of cytotoxic T cells [Klein et at., J. Toxicol. Environ. Health (1991) 32, 465-477], inhibition of the microbicidal activity of macrophages and of TNF-a synthesis [Arata, S. et at.. Life Sci. (1991) 49, 473-479 Fisher-Stenger et al., J. Pharm. Exp. Then (1993) 267, 1558-1565] and inhibition of the cytolytic activity and the TNFa production of large granular lymphoc3rtes [Kusher et al.. Cell. Immun. (1994) 154, 99-108],... 

Abstract Marijuana and other exogenous cannabinoids alter immune function and decrease host resistance to microbial infections in experimental animal models and in vitro. Two modes of action by whichA -tetrahydrocannabinol (THC) and other cannabinoids affect immune responses have been proposed. First, cannabinoids may signal through the cannabinoid receptors CBi and CB2. Second, at sites... 

Early in vitro and in vivo studies indicated that marijuana as well as cannabinoids derivative of this plant, particularly THC, had immunosuppressive properties. These compounds were found to exert a wide range of effects on a variety of immune functions from a diverse array of immune cell types. Such effects were observed for immune cells derivative of various rodents and for cell lines exhibiting... 

Cannabinoids are marijuana components known to modulate immune functions. A-9-tetrahydrocannabinol (A -THC), the major psychoactive compound of marijuana, has been the most widely studied cannabinoid. However, synthetic cannabinoids and the recently discovered endogenous cannabinoids... 

These smoked substances interact with the brain s own cannabinoid receptors to trigger dopamine release from the mesolimbic reward system. There are two known cannabinoid receptors, CB1 (in the brain, which is coupled via G proteins and modulates adenylate cyclase and ion channels) and CB2 (in the immune system). The CB1 receptors may mediate not only marijuana s reinforcing properties, but also those of alcohol. There is also an endogenous cannabinoid system (the brain s own marijuana) capable of activating these cannabinoid receptors functionally. These ert-docannabinoids are synthesized by neurons and inactivated by reuptake systems and enzymes in both neurons and glia. 

Much research has focused on marijuana s effects on the immune system. Some research has shown that one type of immune system cell called the macrophage (scavenger cell) is particularly sensitive to THC exposure. Macrophages clear the body of viruses, bacteria, and particles that are inhaled or ingested. These studies found the presence of cannabinoid receptors on macrophages, suggesting that THC can disrupt normal immune system functions and may eventually inhibit the body s natural immune response. 

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