Proteins That Facilitate HIV Transmission Could Be Targeted for Preventive Therapies, Scientists Report

The discovery of two proteins found on certain human cells that appear to help HIV infect the T cells of the immune system may help scientists create new preventive HIV therapies, Reuters Health reports. In a study published in the Dec. 7 issue of Science, Dr. Bill Weis of Stanford University and colleagues examined the proteins known as DC-SIGN and DC-SIGNR. DC-SIGN is found on the surface of cells that line the cervix, uterus and rectum, while DC-SIGNR is found on the lining of capillaries in the placenta and lymph nodes. Weis noted that these locations constitute some of the "primary sites of infection" where HIV is commonly transmitted either sexually or through mother-to-child transmission (Hitt, Reuters Health, 12/7). Researchers found that the DC-SIGN and DC-SIGNR proteins act as receptors that bind to carbohydrate molecules located on the envelope of the HIV, and this interaction "strongly promotes viral infection of T cells" (Feinberg et al., Science, 12/7). "We hope to use this information in collaboration with chemists to design therapeutic agents that would block HIV's ability to attach to these receptors," Weis said. Such a treatment would reduce the amount of the virus that is delivered to the T cells, thus "reducing the efficiency or probability of infection," he stated. Weis noted that therapies targeting this virus-receptor interaction would probably be useful only as a preventive measure and not as a treatment for existing HIV infection (Reuters Health, 12/7).