Retroviruses are not only important in immunity of an organism but also with thier evolution. Some retroviruses, known as endogenous retroviruses, have even been successful to get incorporated into our genome and represent roughly 8% of human genome. Last month, a colleague of mine at UCSF in collaboration with University of Toronto published a paper in Plos Pathogens regarding the role of Human Endogenous Retroviruses on HIV infection.
The collaborating team found increased levels of HERV production in HIV-1 infected patients and showed that HIV-1 virus causes expression of HERV particles on cells which are recognized by cytotoxic immune cells. These HERV specific cytotoxic (CD8 T cells) that recognize HERV may end up increasing immune response against HIV-1 virus. The increased immunity by HERV can be indirect or direct. The cells that are expressing HERV are killed by immune cells and thus the HIV replicating inside these cells are also killed. This is the indirect effect of HERV on HIV. Also, some of the HERV proteins, very similar to HIV-1 proteins causes some cytotoxic immune cells to recognize cells expressing HIV-1 proteins and kill them directly. Thus, there is a serious potential of using HERV for vaccines.
This news must have been very big because the article was featured by The San Francisco Chronicle and CBC news of Canada. I even found the same work quoted by Michael Specter in a recent issue of The New Yorker. Interestingly Michael’s article, although in a non scientific journal is one of the best reviews on HERV that I have ever read.