scholarly journals The Adenylate Cyclase Toxin of Bordetella pertussis Binds to Target Cells via the αMβ2 Integrin (Cd11b/Cd18)

2001 ◽  
Vol 193 (9) ◽  
pp. 1035-1044 ◽  
Author(s):  
Pierre Guermonprez ◽  
Nadia Khelef ◽  
Eric Blouin ◽  
Philippe Rieu ◽  
Paola Ricciardi-Castagnoli ◽  
...  

The adenylate cyclase toxin (CyaA) of Bordetella pertussis is a major virulence factor required for the early phases of lung colonization. It can invade eukaryotic cells where, upon activation by endogenous calmodulin, it catalyzes the formation of unregulated cAMP levels. CyaA intoxication leads to evident toxic effects on macrophages and neutrophils. Here, we demonstrate that CyaA uses the αMβ2 integrin (CD11b/CD18) as a cell receptor. Indeed, the saturable binding of CyaA to the surface of various hematopoietic cell lines correlated with the presence of the αMβ2 integrin on these cells. Moreover, binding of CyaA to various murine cell lines and human neutrophils was specifically blocked by anti-CD11b monoclonal antibodies. The increase of intracellular cAMP level and cell death triggered by CyaA intoxication was also specifically blocked by anti-CD11b monoclonal antibodies. In addition, CyaA bound efficiently and triggered intracellular cAMP increase and cell death in Chinese hamster ovary cells transfected with αMβ2 (CD11b/CD18) but not in cells transfected with the vector alone or with the αXβ2 (CD11c/CD18) integrin. Thus, the cellular distribution of CD11b, mostly on neutrophils, macrophages, and dendritic and natural killer cells, supports a role for CyaA in disrupting the early, innate antibacterial immune response.

2000 ◽  
Vol 68 (12) ◽  
pp. 7152-7155 ◽  
Author(s):  
Christine L. Weingart ◽  
Paula S. Mobberley-Schuman ◽  
Erik L. Hewlett ◽  
Mary C. Gray ◽  
Alison A. Weiss

ABSTRACT A previous study showed that opsonization with human immune serum could either promote or antagonize phagocytosis of Bordetella pertussis by human neutrophils depending on whether the bacteria expressed adenylate cyclase toxin. Opsonization of the wild-type strain inhibited phagocytosis relative to unopsonized controls. In contrast, mutants lacking adenylate cyclase toxin were efficiently phagocytosed when opsonized with human immune serum. In this study, we examined opsonization in the presence or absence of monoclonal antibodies to adenylate cyclase toxin. Addition of neutralizing monoclonal antibodies to adenylate cyclase toxin converted a serum that previously inhibited both attachment and phagocytosis of the wild-type strain to one that increased both attachment and phagocytosis compared to the no-serum control. Monoclonal antibodies that recognize the adenylate cyclase toxin but fail to neutralize activity were without effect. These results suggest that adenylate cyclase toxin inhibits both Fc receptor-mediated attachment and phagocytosis of B. pertussis by neutrophils.


2014 ◽  
Vol 82 (12) ◽  
pp. 5256-5269 ◽  
Author(s):  
Joshua C. Eby ◽  
Mary C. Gray ◽  
Erik L. Hewlett

ABSTRACTThe adenylate cyclase toxin (ACT) ofBordetella pertussisintoxicates target cells by generating supraphysiologic levels of intracellular cyclic AMP (cAMP). Since ACT kills macrophages rapidly and potently, we asked whether ACT would also kill neutrophils. In fact, ACT prolongs the neutrophil life span by inhibiting constitutive apoptosis and preventing apoptosis induced by exposure to liveB. pertussis. Imaging ofB. pertussis-exposed neutrophils revealed thatB. pertussislacking ACT induces formation of neutrophil extracellular traps (NETs), whereas wild-typeB. pertussisdoes not, suggesting that ACT suppresses NET formation. Indeed, ACT inhibits formation of NETs by generating cAMP and consequently inhibiting the oxidative burst. Convalescent-phase serum from humans following clinical pertussis blocks the ACT-mediated suppression of NET formation. These studies provide novel insight into the phagocyte impotence caused by ACT, which not only impairs neutrophil function but also inhibits death of neutrophils by apoptosis and NETosis.


mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Aya Fukui-Miyazaki ◽  
Hirono Toshima ◽  
Yukihiro Hiramatsu ◽  
Keisuke Okada ◽  
Keiji Nakamura ◽  
...  

ABSTRACTBordetella pertussis,Bordetella bronchiseptica, andBordetella parapertussisshare highly homologous virulence factors and commonly cause respiratory infections in mammals; however, their host specificities and disease severities differ, and the reasons for this remain largely unknown. Adenylate cyclase toxin (CyaA) is a homologous virulence factor that is thought to play crucial roles inBordetellainfections. We herein demonstrate that CyaAs function as virulence factors differently betweenB. bronchiseptica/B. parapertussisandB. pertussis.B.bronchisepticaCyaA bound to target cells, and its enzyme domain was translocated into the cytosol similarly toB.pertussisCyaA. The hemolytic activity ofB.bronchisepticaCyaA on sheep erythrocytes was also preserved. However, in nucleated target cells,B.bronchisepticaCyaA was phosphorylated at Ser375, which constitutes a motif (RSXpSXP [pS is phosphoserine]) recognized by the host factor 14-3-3, resulting in the abrogation of adenylate cyclase activity. Consequently, the cytotoxic effects ofB.bronchisepticaCyaA based on its enzyme activity were markedly attenuated.B.parapertussisCyaA carries the 14-3-3 motif, indicating that its intracellular enzyme activity is abrogated similarly toB.bronchisepticaCyaA; however,B.pertussisCyaA has Phe375instead of Ser, and thus, was not affected by 14-3-3. In addition,B.pertussisCyaA impaired the barrier function of epithelial cells, whereasB.bronchisepticaCyaA did not. Rat infection experiments suggested that functional differences in CyaA are related to differences in pathogenicity betweenB. bronchiseptica/B.parapertussisandB. pertussis.IMPORTANCEBordetella pertussis,B. bronchiseptica, andB. parapertussisare bacterial respiratory pathogens that are genetically close to each other and produce many homologous virulence factors; however, their host specificities and disease severities differ, and the reasons for this remain unknown. Previous studies attempted to explain these differences by the distinct virulence factors produced by eachBordetellaspecies. In contrast, we indicated functional differences in adenylate cyclase toxin, a homologous virulence factor ofBordetella. The toxins ofB. bronchisepticaand presumablyB. parapertussiswere inactivated by the host factor 14-3-3 after phosphorylation in target cells, whereas theB. pertussistoxin was not inactivated because of the lack of the phosphorylation site. This is the first study to show that 14-3-3 inactivates the virulence factors of pathogens. The present results suggest that pathogenic differences inBordetellaare attributed to the different activities of adenylate cyclase toxins.


2011 ◽  
Vol 80 (2) ◽  
pp. 850-859 ◽  
Author(s):  
Joshua C. Eby ◽  
Mary C. Gray ◽  
Annabelle R. Mangan ◽  
Gina M. Donato ◽  
Erik L. Hewlett

ABSTRACTThe adenylate cyclase toxin (ACT) ofBordetella pertussisdoes not require a receptor to generate intracellular cyclic AMP (cAMP) in a broad range of cell types. To intoxicate cells, ACT binds to the cell surface, translocates its catalytic domain across the cell membrane, and converts intracellular ATP to cAMP. In cells that express the integrin CD11b/CD18 (CR3), ACT is more potent than in CR3-negative cells. We find, however, that the maximum levels of cAMP accumulation inside CR3-positive and -negative cells are comparable. To better understand how CR3 affects the generation of cAMP, we used Chinese hamster ovary and K562 cells transfected to express CR3 and examined the steps in intoxication in the presence and absence of the integrin. The binding of ACT to cells is greater in CR3-expressing cells at all concentrations of ACT, and translocation of the catalytic domain is enhanced by CR3 expression, with ∼80% of ACT molecules translocating their catalytic domain in CR3-positive cells but only 25% in CR3-negative cells. Once in the cytosol, the unregulated catalytic domain converts ATP to cAMP, and at ACT concentrations >1,000 ng/ml, the intracellular ATP concentration is <5% of that in untreated cells, regardless of CR3 expression. This depletion of ATP prevents further production of cAMP, despite the CR3-mediated enhancement of binding and translocation. In addition to characterizing the effects of CR3 on the actions of ACT, these data show that ATP consumption is yet another concentration-dependent activity of ACT that must be considered when studying how ACT affects target cells.


2000 ◽  
Vol 68 (3) ◽  
pp. 1735-1739 ◽  
Author(s):  
Christine L. Weingart ◽  
Alison A. Weiss

ABSTRACT The interaction between human neutrophils and wild-typeBordetella pertussis or mutants expressing altered lipopolysaccharide or lacking virulence factors—pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, filamentous hemagglutinin (FHA), pertactin, or BrkA—was examined. In the absence of antibodies, the wild-type strain and the mutants, with the exception of mutants lacking FHA, attached efficiently to neutrophils. The addition of opsonizing antibodies caused a significant reduction (approximately 50%) in attachment of the wild-type strain and most of the mutants expressing FHA, suggesting that bacterium-mediated attachment is more efficient than Fc-mediated attachment. Phagocytosis was also examined. In the absence of antibodies, about 12% of the wild-type bacteria were phagocytosed. Opsonization caused a statistically significant reduction in phagocytosis (to 3%), possibly a consequence of reduced attachment. Phagocytosis of most of the mutants was similar to that of the wild type, with the exception of the mutants lacking adenylate cyclase toxin. About 70% of the adenylate cyclase toxin mutants were phagocytosed, but only in the presence of opsonizing antibody, suggesting that Fc receptor-mediated signaling may be needed for phagocytosis. These studies indicate that FHA mediates attachment ofB. pertussis to neutrophils, but adenylate cyclase toxin blocks phagocytosis.


2004 ◽  
Vol 53 (6) ◽  
pp. 1709-1719 ◽  
Author(s):  
M. C. Gray ◽  
G. M. Donato ◽  
F. R. Jones ◽  
T. Kim ◽  
E. L. Hewlett

Toxins ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 169 ◽  
Author(s):  
Oliver Knapp ◽  
Roland Benz

The Gram-negative bacterium Bordetella pertussis is the cause of whooping cough. One of its pathogenicity factors is the adenylate cyclase toxin (CyaA) secreted by a Type I export system. The 1706 amino acid long CyaA (177 kDa) belongs to the continuously increasing family of repeat in toxin (RTX) toxins because it contains in its C-terminal half a high number of nine-residue tandem repeats. The protein exhibits cytotoxic and hemolytic activities that target primarily myeloid phagocytic cells expressing the αMβ2 integrin receptor (CD11b/CD18). CyaA represents an exception among RTX cytolysins because the first 400 amino acids from its N-terminal end possess a calmodulin-activated adenylate cyclase (AC) activity. The entry of the AC into target cells is not dependent on the receptor-mediated endocytosis pathway and penetrates directly across the cytoplasmic membrane of a variety of epithelial and immune effector cells. The hemolytic activity of CyaA is rather low, which may have to do with its rather low induced permeability change of target cells and its low conductance in lipid bilayer membranes. CyaA forms highly cation-selective channels in lipid bilayers that show a strong dependence on aqueous pH. The pore-forming activity of CyaA but not its single channel conductance is highly dependent on Ca2+ concentration with a half saturation constant of about 2 to 4 mM.


Toxins ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 302 ◽  
Author(s):  
Alexandre Chenal ◽  
Daniel Ladant

The adenylate cyclase toxin (CyaA) is one of the major virulence factors of Bordetella pertussis, the causative agent of whooping cough. CyaA is able to invade eukaryotic cells where, upon activation by endogenous calmodulin, it synthesizes massive amounts of cAMP that alters cellular physiology. The CyaA toxin is a 1706 residues-long bifunctional protein: the catalytic domain is located in the 400 amino-proximal residues, whereas the carboxy-terminal 1306 residues are implicated in toxin binding to the cellular receptor, the αMβ2 (CD11b/CD18) integrin, and subsequently in the translocation of the catalytic domain across the cytoplasmic membrane of the target cells. Indeed, this protein is endowed with the unique capability of delivering its N-terminal catalytic domain directly across the plasma membrane of eukaryotic target cells. These properties have been exploited to engineer the CyaA toxin as a potent non-replicating vector able to deliver antigens into antigen presenting cells and elicit specific cell-mediated immune responses. Antigens of interest can be inserted into the CyaA protein to yield recombinant molecules that are targeted in vivo to dendritic cells, where the antigens are processed and presented by the major class I and class II histocompatibility complexes (MHC-I and II). CyaA turned out to be a remarkably effective and versatile vaccine vector capable of inducing all the components of the immune response (T-CD4, T-CD8, and antibody). In this chapter, we summarize the basic knowledge on the adenylate cyclase toxin and then describe the application of CyaA in vaccinology, including some recent results of clinical trials of immunotherapy using a recombinant CyaA vaccine.


2016 ◽  
Vol 24 (1) ◽  
Author(s):  
Joshua C. Eby ◽  
Mary C. Gray ◽  
Jason M. Warfel ◽  
Tod J. Merkel ◽  
Erik L. Hewlett

ABSTRACT Adenylate cyclase toxin (ACT) is an essential virulence factor of Bordetella pertussis, and antibodies to ACT protect against B. pertussis infection in mice. The toxin is therefore a strong candidate antigen for addition to future acellular pertussis vaccines. In order to characterize the functionality of the immunologic response to ACT after infection, we developed an assay for testing the ability of serum samples from subjects infected with B. pertussis to neutralize ACT-induced cytotoxicity in J774 macrophage cells. Baboons develop neutralizing anti-ACT antibodies following infection with B. pertussis, and all sera from baboons with positive anti-ACT IgG enzyme-linked immunosorbent assay (ELISA) results neutralized ACT cytotoxicity. The toxin neutralization assay (TNA) was positive in some baboon sera in which ELISA remained negative. Of serum samples obtained from humans diagnosed with pertussis by PCR, anti-ACT IgG ELISA was positive in 72%, and TNA was positive in 83%. All samples positive for anti-ACT IgG ELISA were positive by TNA, and none of the samples from humans without pertussis neutralized toxin activity. These findings indicate that antibodies to ACT generated following infection with B. pertussis consistently neutralize toxin-induced cytotoxicity and that TNA can be used to improve understanding of the immunologic response to ACT after infection or vaccination.


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