Discovering innate memory

Harvard researchers have discovered that natural killer cells have memory and can mount antigen-specific responses, similar to T cells and B cells. The finding indicates that the innate immune system is not as static as has been believed.

"The standard textbooks for the past two decades have said that you can divide the immune system into an adaptive and an innate arm," said Ulrich von Adrian, professor in the Department of Pathology at Harvard Medical School, whose laboratory published the finding in Nature Immunology. Under this definition, the adaptive response is an acquired one that evolves as it is exposed to antigens. The innate system, which includes cells like granulocytes, macrophages and NK cells, was not believed to have this adaptive capability. Instead, the innate system was thought to be hardwired to recognize and attack common non-self antigens...