Functional common gamma chain is not required for mast cell proliferation and survival
© Chapdelaine et al; licensee BioMed Central Ltd. 2012
Published: 2 November 2012
IL-15 is involved in the development and homeostasis of CD8 lymphocytes, NK and iNKT cells, and intraepithelial lymphocytes. It also promotes migration, proliferation and survival of mast cells. Its receptor on lymphocytes is a heterotrimeric complex which shares the IL2-Rβ and common gamma ( γc ) chains. IL-15-mediated signaling in mast cells might make use of an alternative receptor provisionally designated as IL-15RX. In a murine model, γc-dependent signaling was shown to be essential for IL-4– and IL-9–induced proliferation and survival of mast cells, but not IL-15 even in the wild-type mouse.
Skin biopsies of BCGitis lesions from 6 X-SCID patients were reviewed. Immunostaining using anti-CD117 ( 1/400, DAKO lab ) and tryptase ( 1/400, DAKO lab ) antibodies was performed. A similar BCGitis lesion from a patient with RAG SCID was tested with the same 2 antibodies as controls.
Mast cells were present in the skin biopsies of all patients presenting with X-SCID ; their number was not decreased compared to normal skin biopsies. The number of mast cells in the skin biopsy of the RAG SCID patient was also normal.
These results suggest that, in humans, γc is not required for mast cell proliferation and survival. Its impact on IL-15-dependent migration and the possible role of IL-15RX warrant further studies.
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