Macrophage Activation Mechanisms in Human Monocytic Cell Line-derived Macrophages

Background: Although the mechanisms of macrophage activation are important for cancer immunotherapy, they are poorly understood. Recently, easy and robust assay systems for assessing the macrophage-activating factor (MAF) using monocytic cell line-derived macrophages were established. Materials and Methods: Gene-expression profiles of U937- and THP-1-derived macrophages were compared using gene expression microarray analysis and their responses against several MAFs were examined by in vitro experiments. Results: Activated states of these macrophages could not be assigned to a specific sub-type but showed, however, different unique characteristics. Conclusion: The unique of monocytic cell line-derived macrophages could provide clues to understand the activation mechanism of macrophages and, therefore, help to develop effective cancer immunotherapy with MAFs.