Molecules of the Innate Immune Response

It is well established that drugs of abuse are involved in a wdde range of immunomodulatory activities. Among the areas in immune system function in which these alterations have been observed is innate immunity. This arm of the immune system does not exhibit specificity in recognizing foreign pathogens. It encompasses NK cells and the professional phagocytic 

The cannabinoids represent another class of abused dmgs affecdng immune cell funcdon. Although few er studies have explored the effects of cannabinoids on NK cells, the literature to date show s that the acdvity of splenic NK cells is suppressed follow ing in vivo injecdon of A -THC into rats and mice (Patel et al., 1985 Klein et al., 1987), and also after in vidro treatment of human peripheral blood NK cells (Specter et al., 1986). A -THC has also been show n to block proliferadon of NK cells in response to the cytokine, IL-2, by dow n-regulating the IL-2 receptor (Zhu et al., 1993). 

There are a limited number of reports of immunomoduladon by cocaine. In vivo aclminisdradon of cocaine i.v. to humans elevated NK cell acdvity in peripheral blood, but exposure of leukocytes to the drug in vidro had no effect (Van Dyke et al., 1986). It W as hypothesized that the in vivo effects occurred via release of epinephrine from the SNS (Van Dyke et al., 1986). CondracUctory results have been reported for the effect of cocaine on NK acdvity in rats, w ith no effect in vivo (Bayer et al., 1996) or suppression of acdvity after acute or chronic in vivo aclminisdradon (Pacifici et al., 2003). 

Drugs of Abuse Alter Functions of PMN Leukocytes and Monocytes/Macrophages 

Cocaine, like A -THC and morphine, has been reported to decrease the anti microbial acdvity of alveolar macrophages obtained from chronic crack cocaine smokers (Roth et al., 2004) and to decrease parameters of mouse macrophage acdvadon (Ou et al., 1989 Pacifici et al., 1993). However, in contrast to the effects of opioids, cocaine has been shown to increase the acdvadon of PMNs in human subjects, as evidenced by increased killing of Staphylococcus aureus (Baldwin et al., 1997). 

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