MPEG1 and bacterial infectious disease: Recent studies in vertebrates (mammalia) demonstrate that expression of Perforin-2 is not limited to macrophages, as it was also detected in murine embryonic fibroblasts (MEF) and human epithelial cells after bacterial infection (Fields et al., 2013; McCormack et al., 2013a) suggesting that Perforin-2 expression is tied to antibacterial activity.