Scientists unveil new mechanism by which body fights viruses

Washington, June 17 : Scientists at the La Jolla Institute for Allergy and Immunology (LIAI) have unearthed a hitherto unknown mechanism by which the body fights a virus.

The researchers say that their findings contradict traditional scientific understanding of this process.

They hope scientists may derive some valuable information from their work to develop new vaccines.

"Our research grew from the question, 'why do you get good antibody responses to some parts of (virus) pathogens and poor responses to other parts?'" said Dr. Shane Crotty, the principal researcher behind this work.

"Selective CD4 T cell help for antibody responses to a large viral pathogen: deterministic linkage of specificities," he added.

Dr. Crotty revealed that working in collaboration with Dr. Alessandro Sette, a renowned vaccine expert and director of the LIAI Center for Infectious Disease, he and his colleagues studied the smallpox vaccine, considered the "gold standard" of vaccines.

Telling about how their efforts provided some startling answers, he said: "We expected one thing based on textbook knowledge and that didn't happen at all."

The researcher said that his team has found that two different cells of the immune system called B cells and CD4 T cells, both known as soldiers in the immune system's defensive army, recognize the same piece of the virus.

"Previously, it was thought that the CD4 T cell could react to any part of the virus, but now we realize it must be specific to the same part as the B cell. When you have a hundred different parts, this knowledge makes a big difference. It narrows down the search for the right antigens tremendously," Dr. Crotty said.

Pointing out that scientists use knowledge of which antigens (virus pieces) trigger an antibody attack to develop vaccines, Dr. Crotty said that the knowledge his team had gained might make it easier to figure out the most important viral pieces to focus on in developing a vaccine.

"The fact that it requires two components to fight the (virus) pathogen is important to understand. So now when we find out which viral pieces are producing a strong response from the B cells, we can cross check that against the viral pieces eliciting a good response from the CD4 T cells. The point at which these virus pieces cross - in other words where the same piece is eliciting a response from both the B cells and CD4 T cells - then we know we have found our best candidate for creating a vaccine," he said.

ANI