Focusing on mouse lymph nodes the Scientists from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), discovered that immune cells confront viruses just inside of the lymph node and not deep within these organs as previously thought.
The results are significant, the study authors say, as they observed in detail the interaction of viruses and immune cells inside a living organism, in this case, mice. Combining expertise from disciplines such as imaging, immunology, virology and other specialties, the scientists first extracted and then purified specific T cells—killer T cells—from mice. Killer T cells, which attack and kill infected or cancerous cells, are major weapons in the immune system arsenal. The scientists labeled the T cells with a fluorescent marker, injected them back into the mice, and then infected the animals with vaccinia virus, the virus used to make smallpox vaccine, engineered to express a brilliantly colored protein.
Using a multiphoton microscope the scientists could now look into the lymph nodes of the infected mice and see that the viruses had infected cells just inside the lymph node surface, triggering a swarm of T cells. These virus-specific T cells form an elaborate and dynamic communications network that activates them to divide and travel to the site of viral infection, where they kill virus-infected cells.
“A key challenge in viral vaccine research is developing strategies for immunizing against lethal viruses such as HIV that have eluded the standard vaccine approaches,” notes Jonathan Yewdell, M.D., Ph.D., leader of the study. According to the NIAID team, pinpointing where in the lymph node immune cells fight the virus should help efforts to design effective anti-virus vaccines.
MEDICA.de; Source: National Institute of Allergy and Infectious Diseases (NIAID)