Alcohol may make oral HIV transmissions easier

Exposing oral epithelial cells to alcohol may make them more susceptible to HIV infection, according to a study in the December 1 issue of the Journal of Acquired Immune Deficiency Syndromes. Jun-ying Zheng and colleagues at the University of California, Los Angeles, Dental Institute exposed primary oral epithelial cells from HIV-negative study subjects to various concentrations of alcohol, then exposed the cells to a specially engineered strain of HIV with a fluorescent green protein so that infections could be easily detected. Cells exposed to a 4% ethanol solution for 10 minutes showed a three- to six-fold greater susceptibility to HIV infection than cells not exposed to alcohol. Additional tests showed that the increased susceptibility was not due to alcohol's effect on viral activity but by its effects on the cells. The researchers say that the 4% ethanol concentration studied is similar to the alcohol content of beer and considerably lower than the alcohol content of wine and other hard liquors. "In cell culture conditions, the ranges of concentrations of alcohol that are commercially available are able to stimulate the infection efficiency of HIV in primary oral epithelial cells," the researchers conclude. The researchers are unclear exactly how HIV entered the oral epithelial cells because they lack a key receptor necessary for viral infection, but they theorize that the alcohol either alters the cellular membranes to facilitate viral entry or interacts with key proteins to enable cellular fusion and infection. Additional studies are planned.