We derived and characterized a human MC line that arose spontaneously from a culture of nontransformed hematopoietic progenitor cells.
CD34+ enriched mononuclear cells derived from a donor with aspirin-exacerbated respiratory disease were cultured for 8 weeks with stem cell factor and IL-6 and with IL-3 for the first week only. The cells (termed LUVA cells) survived and proliferated without further addition of any growth factors and have been maintained in culture for approximately 2 years.
LUVA cells possess metachromatic cytoplasmic granules that are immunoreactive for tryptase, cathepsin G, and carboxypeptidase A3. They express transcripts encoding Fcx3b5;RI, c-kit, chymase, tryptase, histidine decarboxylase, carboxypeptidase A3, and the type 1 receptor for cysteinyl leukotrienes. Flow cytometry confirmed uniform expression of Fcx3b5;RI, c-kit, and FcγRII. Fcx3b5;RI cross-linkage induced the release of β-hexosaminidase, prostaglandin D2, thromboxane A2, and macrophage inflammatory protein 1β. Immortalization was not associated with either a known genomic mutation of c-kit in the donor or a somatic mutation of c-kit within the cells, and it was not associated with c-kit autophosphorylation.
LUVA cells are an immortalized human MC line that can be maintained without stem cell factor and display high levels of normally signaling c-kit and Fcx3b5;RI. These cells will prove valuable for functional human MC studies.