Organisms develop coping mechanisms to protect themselves from adverse conditions. In a more advanced way, bacteria and viruses also use these mechanisms, but are even able to camouflage themselves against the attacker — their host's immune system. One such virus is the Kaposi's sarcoma-associated herpesvirus (KSHV), which successfully avoids detection from our immune system and proliferates inside the human body without being recognized.
Research on the virus was carried out at the Helmholtz Centre for Infection Research (HZI) in Braunschweig, and a paper on their work was published in the Journal of Virology, according to a press release.
KSHV, or HHV-8, as it is formally called, is an oncovirus responsible for a range of diseases including, primary effusion lymphoma and some types of Castleman's disease. But it is mostly associated with Kaposi's sarcoma, a cancer occurring in immunosuppressed AIDS patients. It is a gammaherpesvirus, a virus that remains dormant until it's able to establish lifelong infections in its host.
Generally, when viruses attack the body, they are “fought off immediately by an antiviral immune response that is triggered by sensors including the toll-like receptors (TLR)," HZI researcher and author of the study Dr. Kendra Bussey said in the release. TLR are a class of proteins that are expressed on the surface of the immune system’s fighter cells, including macrophages and dendritic cells. TLRs identify pathogens based on certain patterns called pathogen-associated molecular patterns (PAMPs) displayed on their surfaces or DNA. This recognition then triggers a series of immune response pathways that flush out the pathogen.
But this recognition does not seem to work against KSHV or other kinds of gammaherpesviruses, and enables them to remain in the host's body for life. The HZI scientists detected their concealment mechanism while part of a research group called "Viral Immune Modulation.” Led by Professor Melanie Brinkmann, the group was able to show that the virus was somehow bypassing detection by messing up a function of the TLR, although exactly which part and how it's done has yet to be discovered.
The scientists are optimistic that this finding will help in the development of therapeutic options against gammaherpesviruses. “Those agents could actively protect the immune system and prevent viruses from winning the fight against it," Bussey said in the release. "However, this is still a long way off."
There are still a number of pathogens whose methods of invading and causing disease in the human body need to be researched. The "Viral Immune Modulation" group seeks to shed light on these viruses and their mechanisms, particularly that of the herpes viruses.
Source: Bussey K, Reimer E, Todt H, et al. The gammaherpesviruses KSHV and MHV68 modulate the TLR-induced proinflammatory cytokine response. Journal of Virology. 2014.