Scientists gain new view of immunity

WASHINGTON, April 17 (UPI) -- U.S. government scientists announced Monday they have gained a new understanding of how long-term immunity works.

The researchers from the National Institute of Allergy and Infectious Diseases say their findings may lead to new ways of enhancing certain immune responses and how to improve vaccines.

Led by immunologist Dr. Ronald Germain, the scientists took videos through a microscope to document what happens inside the lymph nodes of a living mouse shortly after a vaccination.

The videos reveal the movement of a specific type of immune cell known as a cytotoxic T cell is not random as was previously thought, but instead is guided by chemical signals released from other cells.

The researchers found when cytotoxic T cells enter a lymph node, a combination of specific physical and chemical cues guides them to sites where they receive activation signals.

"Understanding the processes whereby (cytotoxic T cells) find their way in the lymph nodes is important because their activation is essential for eliminating infected cells and for providing, together with antibodies, long-lasting protection following vaccinations," said NIAID Director Dr. Anthony S. Fauci.

The findings are detailed in the current issue of the journal Nature.