September 30, 2014

By: douano@listlabs.com

Adenylate cyclase toxin-hemolysin (ACT, AC-Hly, or CyaA) is an important virulence factor for Bordetella pertussis.  Adenylate cyclase toxin is a large (178 kDa), 1,706-residue-long, toxin consisting of an amino-terminal adenylate cyclase (AC) domain of 400 residues and a repeat toxin (RTX) moiety of 1,306 residues.  Sequences within the RTX domain are responsible for target binding, pore-formation and calcium binding.  Also located within this domain are two lysine residues which undergo posttranslational modified by acylation (1).

Adenylate cyclase toxin targets sentinel cells of the host’s innate immune defense. It penetrates a variety of immune cells and, when activated by calmodulin, catalyzes conversion of cellular ATP to cyclic AMP (cAMP), interfering with cell signaling and with the anti-bacterial activity of phagocytes. ACT acts on phagocytes limiting the phagocytes ability to produce oxidative burst and kill bacterial through complement or antibodies (2, 3).  The entire AC-Hly protein is necessary for adenylate cyclase delivery into cells (4).

In the intoxication process, the Hly portion of the toxin binds to CR3 receptor on target cells (CD11b⁺) and allows translocation of the AC enzyme into the cell.  Within the target cell, adenylate cyclase rapidly produces extremely high levels of cAMP, disabling the immune cell (5, 6).  At a lower efficiency, adenylate cyclase-hemolysin can penetrate cells lacking the CR3 receptor and create cAMP (7). In addition to binding target cells, CyaA is able to form small cation-selective pores in cytoplasm membranes, causing hemolysis in erythrocytes (8).

A non-enzymatic, genetically detoxified CyaA-AC^– toxoid has been produced (9). Although the catalytic activity in this AC toxoid is destroyed, it is still cell invasive and able to induce an immune response to co-administered pertussis antigens (10, 11, 12).  This toxoid has been shown to be capable of delivering vaccine antigens into the cytosol of major Histocompatibility complex (MHC) class I antigen-presenting cells (13).CyaA-AC^– toxoid has been used as a tool to deliver antigens to T cells in anti-cancer immunotherapeutic vaccines. (9, 14, 15)

List Labs provides several variations of the B. pertussis Adenylate Cyclase Toxin.  Most recently we have prepared a new formulation of the lyophilized Adenylate Cyclase Toxin Product #188.  This product may be obtained, upon request, as a liquid (Product #188L).  Additionally we have samples available of the Genetically Detoxified CyaA-AC Toxoid, request Product #188X, and samples of an especially low endotoxin preparation of Adenylate Cyclase Toxin Product #188U.  Finally, you will find in our product offering Product #189, Adenylate Cyclase Antigen, Native from Bordetella pertussis.

1. Sebo P., Osicka R., Masin J., (2014) Adenylate cyclase toxin-hemolysin relevance for pertussis vaccines. Expert Review of Vaccines 13(10): 1215-1227. PMID: 25090574
2. Confer DL. and Eaton JW., (1982) Phagocyte impotence caused by an invasive bacterial adenylate cyclase. Science 217:948–950. PMID: 6287574
3. Mock M. and Ullmann A., (1993) Calmodulin-activated bacterial adenylate cyclases as virulence factors. Trends Microbiol 1:187–192. PMID: 8143137
4. Sakamoto H., Bellalou J., Sebo P., Ladant D., (1992) Bordetella pertussis adenylate cyclase toxin. Structural and functional independence of the catalyticand hemolytic activities. J Biol Chem 267:13598–13602. PMID: 1618862
5. Wolff J., Cook GH., Goldhammer AR., Berkowitz SA., (1980) Calmodulin activates prokaryotic adenylate cyclase. Proc Natl Acad Sci USA 77(7):3841-4. PMID: 6253992
6. Hanski E. and Farfel Z., (1985) Bordetella pertussis invasive adenylate cyclase. Partial resolution and properties of its cellular penetration. J Biol Chem 260(9):5526-32. PMID: 2859287
7. Vojtova J., Kamanova J., Sebo P., (2006) Bordetella adenylate cyclase toxin: a swift saboteur of host defense. Curr Opin Microbiol 9(1):69-75. PMID: 16406775
8. Szabo G., Gray MC., Hewlett EL., (1994) Adenylate cyclase toxin from Bordetella pertussis produces ion conductance across artificial lipid bilayers in a calcium and polarity-dependent manner. J Biol Chem 269(36):22496–22499. PMID: 8077197
9. Simsova M., Sebo P., Leclerc C., (2004) The adenylate cyclase toxin from Bordetella pertussis–a novel promising vehicle for antigen delivery to dendritic cells. Int J Med Microbiol 293(7-8):571-6. PMID: 15149033
10. Macdonald-Fyall J., Xing D., Corbel M., Baillie S., Parton R., Coote J., (2004) Adjuvanticity of native and detoxified adenylate cyclase toxin of Bordetella pertussis towards co-administered antigens. Vaccine 22(31-32):4270-81. PMID: 15474718
11. Orr B., Douce G., Baillie S., Parton R., Coote J., (2007) Adjuvant effects of adenylate cyclase toxin of Bordetella pertussis after intranasal immunisation of mice. Vaccine 25(1):64-71. PMID: 16916566
12. Cheung GY., Xing D., Prior S., Corbel MJ., Parton R., Coote JG., (2006) Effect of different forms of adenylate cyclase toxin of Bordetella pertussis on protection afforded by an acellular pertussis vaccine in a murine model. Infect Immun 74(12):6797-805. PMID: 16982827
13. Osicka R., Osicková A., Basar T., Guermonprez P., Rojas M., Leclerc C., Sebo P., (2000) Delivery of CD8(+) T-cell epitopes into major histocompatibility complex class I antigen presentation pathway by Bordetella pertussis adenylate cyclase: delineation of cell invasive structures and permissive insertion sites. Infection Immunity 68: 247-256. PMID: 10603395
14. Dadaglio G., Morel S., Bauche C.,  Moukrim Z., Lemonnier FA., Van Den Eynde BJ., Ladant D., Leclerc C., (2003) Recombinant adenylate cyclase toxin of Bordetella pertussis induces cytotoxic T lymphocyte responses against HLA*0201-restricted melanoma epitopes. Int Immunol 15(12):1423-30. PMID: 14645151
15. Fayolle C., Ladant D., Karimova G., Ullmann A., Leclerc C., (1999) Therapy of murine tumors with recombinant Bordetella pertussis adenylate cyclase carrying a cytotoxic T cell epitope. J Immunol 162(7):4157-62. PMID: 10201941