Human Dendritic Cells Activate Resting Natural Killer (NK) Cells and Are Recognized via the NKp30 Receptor by Activated NK Cells

During the innate response to many inflammatory and infectious stimuli, dendritic cells (DCs) undergo a differentiation process termed maturation. Mature DCs activate antigen-specific naive T cells. Here we show that both immature and mature DCs activate resting human natural killer (NK) cells. Within 1 wk the NK cells increase two-- to fourfold in numbers, start secreting interferon (IFN)-gamma, and acquire cytolytic activity against the classical NK target LCL721.221. The DC-activated NK cells then kill immature DCs efficiently, even though the latter express substantial levels of major histocompatibility complex (MHC) class I. Similar results are seen with interleukin (IL)-2--activated NK cell lines and…

• CR
  Cancer Research Institute
• LR
  Leukemia Research Foundation
• AI
  Associazione Italiana per la Ricerca sul Cancro
• NI
  National Institutes of Health