A novel method to generate and culture human mast cells: Peripheral CD34 + stem cell-derived mast cells (PSCMCs)

The identification and characterization of human mast cell (MC) functions are hindered by the shortage of MC populations suitable for investigation. Here, we present a novel technique for generating large numbers of well differentiated and functional human MCs from peripheral stem cells (= peripheral stem cell-derived MCs, PSCMCs). Innovative and key features of this technique include 1) the use of stem cell concentrates, which are routinely discarded by blood banks, as the source of CD34 + stem cells, 2) cell culture in serum-free medium and 3) the addition of LDL as well as selected cytokines. In contrast to established and published protocols that use CD34 + or CD133 + progenitor cells from full blood, we used a pre-enriched cell population obtained from stem cell concentrates, which yielded up to 108 differentiated human MCs per batch after only three weeks of culture starting with 106 total CD34 + cells. The total purity on MCs (CD117 +, FcεR1 +) generated by this method varied between 55 and 90%, of which 4–20% were mature MCs that contain tryptase and chymase and show expression of FcεRI and CD117 in immunohistochemistry. PSCMCs showed robust histamine release in response to stimulation with anti-FcεR1 or IgE/anti-IgE, and increased proliferation and differentiation in response to IL-1β or IFN-γ. Taken together, this new protocol of the generation of large numbers of human MCs provides for an innovative and suitable option to investigate the biology of human MCs.