Stem cell factor is localized in, released from, and cleaved by human mast cells.

摘要: Stem cell factor (SCF) is the most important cytokine regulating human mast growth and functions. The immunogold technique showed SCF in secretory granules of skin cells lung parenchymal (HLMC). Immunoreactive (iSCF) was detected lysates HLMC, but not basophils; iSCF histamine were supernatants HLMC 3 min after challenge with anti-FceRI or anti-IgE, rapidly declined 30 min, whereas remained unchanged for 120 min. HPLC electrospray mass spectrometry (ES/MS) analysis recombinant SCF1–166 (18,656.9 ± 0.9 Da) treated chymase a polypeptide 17,977.1 0.6 Da minor component 697.4 0.1 generated by specific cleavage at Phe159. SCF1–159 similarly activated potentiated anti-IgE-induced activation these cells, stimulated chemotaxis. SCF159–166 had no effect on cells. Western blot anti-IgE-activated incubated that cleaved to SCF1–144. Experiments yielded similar results. In conclusion, stored immunologically released specifically chymase, which retains its biological also other proteases several species whose possible activities remain be established.