Natural killer cells activate human dermal fibroblasts

Human dermal fibroblasts (HDF) undergo activation and secrete cytokines whe n cocultured with T cells. Here, me identify potent activators of HDF among human peripheral CD2+-lymphocytes. Populations with strong HDF activating capacity consisted essentially of cells with a natural killer (NK) surface marker phenotype (CD3(-), CD4(-), CD8(-), CD56(+)). Addition of these cells to HDF resulted in rapid increase of intracellular free calcium concentrat ions as an early rapid cell activation signal. Upregulation of mRNA encodin g for the inflammatory cytokines IL-1 beta and IL-6 as well as for chemokin es IL-8 and MCP-1 was detected after cells mere cocultured, Elevated concen trations of IL-6 and IL-8 mere found in coculture supernatants of HDF and N K-cells, Skin-homing NK cells leaving the blood-stream during an inflammato ry skin reaction might therefore represent potent activators of local infla mmatory cytokine and chemokine production. (C) 2000 Academic Press.