Cytotoxicity is a crucial effector mechanism for anti-microbial control and for tumor surveillance. Perforin-1, a pore forming protein expressed and secreted through granule exocytosis by NK and CTL, is a central player for cytotoxicity. Unexpectedly, we discovered that Perforin-1 also has homeostatic functions, since its absence together with Fas-L causes spontaneous lethal disease in mice (cdd - cytotoxic double deficient - disease) which is associated with organ invasion by macrophages and CD8 T cells. The subsequent discovery of human Perforin deficiency and its association with the lethal FHL (familial hemophagocytic lympho-histiocytosis) syndrome in children underlined the importance of Perforin in homeostatic regulation. Competing models have been proposed to explain the mechanisms by which Perforin controls macrophage and CD8 T cell-homeostasis. CD8-CTL fratricide has been proposed as a homeostatic control mechanism for CD8 cells by others; we have proposed a model of homeostatic control in which CTL-perforin is required to kill antigen presenting cells (including macrophages) thereby turning off continued CD8 CTL activation. We propose to further study this negative feed back hypothesis in specific aim 1. ? ? A macrophage expressed mRNA predicting a protein with a membrane attack complex/perforin domain has been identified by several groups. However no information about the identity of the predicted protein has been available. We have finally succeeded to conclusively show that the macrophage expressed mRNA encodes a novel pore forming protein with striking similarities, but also with differences, to Perforin-1. We designated the novel macrophage protein as Perforin-2 (P2) in distinction to classical Perforin-1 (P1) expressed by NK and CTL. P2 is a membrane anchored (tethered) protein with a long phylogenetic history going back to early metazoans such as sponge and sea anemone. There is evidence that sponge P2 has anti bacterial activity and that anemones use it to catch prey. We propose the hypothesis that macrophage P2 is a bactericidal protein and may also have anti tumor activity. In addition macrophage P2 mRNA is endowed with fascinating regulatory controls for protein translation while posttranslational mechanisms appear to control P2-protein polymerization and pore-formation. These mechanisms will be studied in specific aim 2. ? ? ?

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Cellular and Molecular Immunology - B Study Section (CMIB)
Program Officer
Mccarthy, Susan A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Miami School of Medicine
Schools of Medicine
Coral Gables
United States
Zip Code
McCormack, Ryan M; Lyapichev, Kirill; Olsson, Melissa L et al. (2015) Enteric pathogens deploy cell cycle inhibiting factors to block the bactericidal activity of Perforin-2. Elife 4:
McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki et al. (2015) Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria. Elife 4:
McCormack, Ryan; de Armas, Lesley R; Shiratsuchi, Motoaki et al. (2013) Inhibition of intracellular bacterial replication in fibroblasts is dependent on the perforin-like protein (perforin-2) encoded by macrophage-expressed gene 1. J Innate Immun 5:185-94
Fields, K A; McCormack, R; de Armas, L R et al. (2013) Perforin-2 restricts growth of Chlamydia trachomatis in macrophages. Infect Immun 81:3045-54
McCormack, Ryan; de Armas, Lesley; Shiratsuchi, Motoaki et al. (2013) Killing machines: three pore-forming proteins of the immune system. Immunol Res 57:268-78
Fang, Lei; Adkins, Becky; Deyev, Vadim et al. (2008) Essential role of TNF receptor superfamily 25 (TNFRSF25) in the development of allergic lung inflammation. J Exp Med 205:1037-48
Xiao, Yanping; Motomura, Seiichi; Podack, Eckhard R (2008) APRIL (TNFSF13) regulates collagen-induced arthritis, IL-17 production and Th2 response. Eur J Immunol 38:3450-8
Oizumi, Satoshi; Deyev, Vadim; Yamazaki, Koichi et al. (2008) Surmounting tumor-induced immune suppression by frequent vaccination or immunization in the absence of B cells. J Immunother 31:394-401
Podack, Eckhard R; Deyev, Vadim; Shiratsuchi, Motoaki (2007) Pore formers of the immune system. Adv Exp Med Biol 598:325-41
Oizumi, Satoshi; Strbo, Natasa; Pahwa, Savita et al. (2007) Molecular and cellular requirements for enhanced antigen cross-presentation to CD8 cytotoxic T lymphocytes. J Immunol 179:2310-7

Showing the most recent 10 out of 62 publications