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

Abstract

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. Mast cells were obtained from the peritoneal cavity of C57BL/6 mice. Mice were injected intraperitoneally twice per day for 5days with IL-3 (40-50μg/ml) to increase mast cell numbers. 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 24h 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. 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. Mast cells cultured from IL-3-treated mice show impaired responses.