Researchers at the University of California Los Angeles (UCLA) have found that two proteins inside dendritic cells stop the virus from “budding,” thus protecting other cells from being infected. The study appears online, ahead of publication in the journal of the Federation of American Societies for Experimental Biology.

Dendritic cells are involved in immune surveillance and protection early in the course of an infection. They’re located predominantly in the skin, mucous membranes (such as the throat or gut) and within lymph nodes. When dendritic cells encounter HIV, they use a protein called DC-SIGN to trap the virus and present it to CD4 cells to spark an immune response.

When HIV infects CD4s, the virus’s genetic material is reproduced and packaged, eventually budding from the cell and moving on to infect other cells. Even though dendritic cells can be infected with HIV, budding does not occur.

Shen Pang, PhD, an associate professor in the division of oral biology and medicine at the UCLA School of Dentistry, and Qiuwei Wang, a graduate student working with Pang, took a closer look at DC-SIGN to see if it prevents dendritic cells from producing new HIV.

Pang found that the presence of DC-SIGN, along with DC-SIGNR, a similar protein, blocked the release of HIV from dendritic cells by 95 to 99.5 percent.  Pang’s group theorizes that the proteins disrupt the ability of HIV to complete its assembly process at the outer membrane of a dentritic cell, thus preventing budding. He is encouraging other researchers to explore how this knowledge may aid efforts to produce an effective HIV vaccine.