Chemokines and CAF May Be Able to Fight AIDS
In this year's International Conference on AIDS, drug therapy wasn't the only hot topic; chemokines are sparking interest also. In addition to being involved in the immune system's normal inflammatory response, chemokines also seem to affect whether or not HIV can infect a cell. Scientists have discovered a chemokine receptor, called CC-CKR5 (cysteine-cysteine chemokine receptor 5), on the surface of immune system cells. HIV binds to this receptor in addition to one called CD4 to enter and infect cells. Chemokine chemicals may inhibit HIV infection by binding to and blocking the CC-CKR5 receptor. Indeed, people of have been infected with the virus but have not developed the disease have high levels of chemokines. Also, CC-CKR5 was found to be defective in individuals who have been exposed to HIV but not infected.

Other data indicates that the levels of chemokines were not different between patients in which the disease was not progressing and those in which it was rapidly progressing. On the other hand, levels of another factor, called CAF (CD8+ cell antiviral factor), were different between these two groups. Unfortunately, researchers have been unable to isolate CAF, which seems not to block receptors that HIV uses to gain entry to cells but to prevent replication of the virus once it has infected the cells. Research continues on the use of chemokines in treatments for HIV infection, either increasing the amount of chemokines or disabling the CC-CKR5 receptor. However, research on CAF indicates that it may be a better target for treatment and prevention of AIDS.

Source: "Chemokines Share Center Stage With Drug Therapies" by Jon Cohen, Science, July 19, 1996