Morphine promotes simian acquired immunodeficiency syndrome virus replication in monkey peripheral mononuclear cells: Induction of CC chemokine receptor 5 expression for virus entry

AIDS is a cellular immune disorder found in patients infected with human immunodeficiency virus (HIV). HIV infection is the leading cause of death among Americans 25‐44 years old, and injection drug use now accounts for about one-third of all new US AIDS cases reported each year [1]. Among drug users, needle sharing alone cannot explain the high levels of infection, since blood volumes transferred by shared needles are small (, 0.75 mL) [2]. Opioid addicts who did not share needles also showed substantial rates of seropositivity to HIV [3], suggesting that opioids themselves may be a contributing factor for exacerbating HIV disease. The complexity of tracing patterns of drug use in individuals and the heterogeneity of human studies present a problem in characterizing the relationship between opioid use and HIV infection. Simian immunodeficiency virus (SIV) has been isolated from nonhuman primate hosts [4], and SIVmac virus (isolated from rhesus macaques) is related to HIV-2 by � 75% nucleotide sequence homology [5]. The mode of infection of rhesus macaques with SIVmac and the resulting clinical symptoms of simian AIDS (SAIDS) are astoundingly similar to those of HIV infection in