When human neutrophils were co-cultured for 72 h with nontransformed human fibroblasts, 69 +/- 3% (n = 13) survived, as compared with survival levels of 2 +/- 1% (n = 15) and 26 +/- 6% (n = 7), respectively, for neutrophils cultured for the same time period in enriched medium alone or supplemented with 10 pM recombinant human granulocyte/macrophage colony-stimulating factor (rh GM-CSF). Conditioned medium from the human fibroblast cultures enhanced neutrophil survival in a dose-dependent fashion to the same level achieved with neutrophil/fibroblast co-cultures, and its soluble viability-sustaining activity was not inhibited by preincubation with neutralizing antiserum against rh GM-CSF. As compared with freshly isolated replicate samples, neutrophils co-cultured with human fibroblasts for 72 h exhibited augmented FMLP-stimulated superoxide production without spontaneous superoxide generation. This striking extension of survival and associated priming for a ligand response by neutrophils co-cultured with human fibroblasts suggests that fibroblasts may contribute to the proinflammatory properties of neutrophils in tissues.
C J Ling, W F Owen Jr, K F Austen
The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.