A major finding by researchers at the La Jolla Institute for Allergy & Immunology (LIAI) has identified a previously unknown cellular mechanism that acts as an off switch for immune system function.
The discovery could lead to the future development of new treatments for autoimmune diseases such as rheumatoid arthritis, multiple sclerosis and Crohn's disease.
In autoimmune diseases, the immune system, which normally wards off invading viruses and bacteria, instead mistakenly attacks normal body tissues, leading to illness. "By understanding this cellular process for turning off immune system activity, we are hopeful this will lead to new treatments that will stop unwanted immune responses, such as those which occur in autoimmune diseases," said LIAI scientist Carl Ware, Ph.D., who co-led the study with LIAI researcher Chris Benedict, Ph.D. The research team also involved scientists from Rush Medical Center and Northwestern University in Chicago and Washington University in St. Louis.
The findings will be published September 13 in the Proceedings of the National Academy of Sciences (PNAS) in a paper entitled, "Evolutionarily Divergent Herpesviruses Modulate T cell activation by Targeting the Herpesvirus Entry Mediator (HVEM) Cosignaling Pathway."
Jennifer Gommerman, Ph.D., and Tania Watts, Ph.D., of the University of Toronto's Department of Immunology, who co-wrote a PNAS commentary on the paper scheduled for online publication this week, called the findings a significant advancement. "This discovery underscores the importance of this pathway in immune regulation and advances our knowledge of how to develop effective treatments for certain illnesses."
In the study, the team of scientists looked at two members of the herpes family of viruses, cytomegalovirus and herpes simplex virus, because of their ability to lay dormant in the immune system without causing disease. "These viruses teach us how to manipulate the immune system," Dr. Ware said. "We found that these two very different viruses were attacking the same communication pathway in the immune system." By disrupting that pathway, the viruses were keeping T lymphocytes - which are white blood cells that fight disease - from communicating with other cells in the immune system. "It's kind of like jamming a phone system," Dr. Ware explained. "If communication gets cut off, messages won't get through and nothing is going to get done."