DURHAM, N.C., March 3 (UPI) -- U.S. medical scientists say they've found a new origin for an immune system response that is critical during the first stages of a viral or bacterial attack.
Duke University Medical Center researchers say they've determined the body's defense against viruses and harmful bacteria comes from an entirely different direction than previously thought.
"This finding will have important implications in vaccine science and autoimmune disease therapy development," said Dr. Michael Gunn, senior author of the study.
Type 1 helper T cell immune responses are critical for the control of viruses and certain bacteria, the researchers said, and until now most immunologists believed TH1 responses were induced by rare immune cells called dendritic cells. When activated by infection or vaccination, the dendritic cells were thought to move from peripheral tissues into lymph nodes to stimulate T cell responses.
The Duke researchers, however, said they discovered the dendritic cells that stimulate TH1 responses didn't come from peripheral tissues but rather arose from monocytes -- a common cell type in the blood -- that moved directly into lymph nodes after infection.
"The result speaks to the most basic principles of immune response to pathogens," Gunn said. "It may also explain the poor results we have seen in attempts to develop effective dendritic-cell vaccines."
The study, which included Hideki Nakano, Kaifeng Lisa Lin, Manabu Yanagita, Chantal Charbonneau, Donald Cook and Terutaka Kakiuchi, appears in the journal Nature Immunology.
