| Abstract |
Mast cells are cells with ubiquitous tissue distribution, derived from
CD34 + multipotent hematopoietic cells. These cells play a fundamental
role in the initiation of innate and adaptive immune response and in
IgE-dependent allergic reactions or in various inflammatory reactions.
Mastocytosis is defined as a myeloproliferative neoplastic disorder,
caused by an abnormal accumulation of mast cells in one or more organ
systems. Mastocytosis presents in cutaneous and systemic forms. In
patients with systemic mastocytosis, the most frequent point mutation is
KIT D816V, whereas in pediatric patients, where the disease is usually
restricted to the skin, different KIT defects have been detected, mostly
in the extracellular portion of KIT. In a primary culture of mast cells
made from precursors of one cord blood, we have successfully isolated a
new human mast cell line called ROSA KIT WT with a phenotype and
reactivity comparable to those of normal mast cells. This cell line is
dependent on SCF for growth and expresses the KIT receptor wild. It is
easy to grow in large quantities, to freeze and to activate by IgE-anti
IgE couple or a couple of allergen and corresponding specific IgE. This
cell line can be used to study pathophysiologic mechanisms of allergy and
to develop and use high-throughput screening tests of molecules in search
of anti-allergic properties.In addition, we transfected these cells by
lentiviral vectors providing constructs encoding the mutated KIT D816V or
the mutated KIT Delta 417-419 insY, two KIT abnormalities encountered in
the course of mastocytosis. This allowed us to establish two new cell
lines independent of SCF for proliferation, ROSA KIT D816V and ROSA KIT
Delta417-419 insY, which are particularly easy to grow in large
quantities, and whose phenotype is similar to that of abnormal mast cells
during mastocytosis. These two cell lines can be used for pathophysiologic
studies on mastocytosis and for high throughput screening of molecules in
search of antiproliferative effects specifically directed against the
mutated KIT or against one or other of the intracellular molecules
involved in signal transduction induced by mutant KIT.
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