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Description:
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One of the most "fashionable" as well as dangerous drugs abused in this country is cocaine . Very little is known about the effects of cocaine on the immune system . Since macrophages play a central role in both the cellular and the humoral arms of the immune system , this study focused on the effects of cocaine on murine peritoneal macrophage functions , viz . , phagocytosis and activation to the cytotoxic state .
Phagocytosis is one of the most important components of the host defenses against invading microorganisms once the outer epithelial surface of the body has been breached . In the present study , cocaine injected intraperitoneally was found to increase phagocytic activity of isolated macrophages in vitro ; but decreased it when measured by an in vivo assay . The respiratory burst , which is usually correlated with phagocytosis , was enhanced by cocaine . Macrophage activation was studied by measuring macrophage - mediated cytotoxicity (MMC ) , i .e . , the acquisition of competence to destroy neoplastic cells in the absence of antibody . Macrophages from cocaine -injected mice demonstrated a reduced capacity for killing neoplastic cells ; as well as a reduction in the secretion of reactive nitrogen intermediates . The latter represent a major product used by macrophages to kill cells . Macrophage receptors / surface proteins involved in phagocytosis and activation were studied using flow cytometry . A number of these surface receptors were dramatically altered by exposure to cocaine . The presumed toxic metabolites of cocaine , benzoylecgonine and norcocaine , were found to have similar effects on macrophage functions .
The present studies clearly demonstrate that cocaine affeas phagocytosis and activation to the cytotoxic state . This translates into impairment of certain non -specific immune responses . These results taken in their entirety suggest that the ability of cocaine to alter macrophage functions could modify specific immune responses resulting in a compromised immune system . |