Mast cells cultured from IL-3-treated mice show impaired responses to bacterial antigen stimulation.

OBJECTIVE AND
DESIGN: This study exploits the biological activity of interleukin (IL)-3 to generate high yields of peritoneal mast cells ex vivo in order to examine pro-inflammatory immune responses in ex-vivo culture. MATERIAL OR
SUBJECTS: Mast cells were obtained from the peritoneal cavity of C57BL/6 mice. TREATMENT: Mice were injected intraperitoneally twice per day for 5 days with IL-3 (40-50 μg/ml) to increase mast cell numbers.
METHODS: Histological studies examined mast cell numbers in the peritoneal cavity, intestine, lung, spleen and skeletal muscle. Peritoneal mast cells cultured ex vivo (PCMCs) were stimulated for 24 h with lipopolysaccharide and Bordetella pertussis antigen and secretion of tumour necrosis factor-α, IL-6, IL-4, IL-5, IL-10 and interferon-γ into supernatant was measured by commercial ELISA. Cell surface marker expression of FcεRI, c-kit, OX40L and TLR2 was measured by flow cytometry. Mast cell degranulation was measured using a β-hexosaminidase assay.
RESULTS: IL-3 treatment increases mast cell numbers in the peritoneal cavity, spleen and muscle but not intestine and lung of C57BL/6 mice. PCMCs generated from IL-3-treated mice exhibit impaired growth, differentiation and responses to activation as measured by decreased cytokine secretion and cell surface marker expression.
CONCLUSION: Mast cells cultured from IL-3-treated mice show impaired responses.