Macrophage-mediated cytotoxicity against rhabdomyosarcoma cells

Background: The prognosis of advanced stage rhabdomyosarcoma (RMS) is still sobering. Therefore, novel therapies such as immunotherapy have to be developed. Methods: Expression of the macrophage activating ligand calreticulin and of the inhibitor CD47 was analyzed on 11 RMS tissue samples using mRNA expression arrays and immunohistochemistry. Results were verified by immunocytochemistry and flow cytometry in 2 RMS cell lines. Cytotoxicity was quantified in co-culture experiments of RMS cells and macrophages using MTT-assays. Results: mRNAs of CD47 and calreticulin were detected in RMS tissues in similar quantiti…