CyaC-mediated activation is important not only for toxic but also for protective activities of Bordetella pertussis adenylate cyclase-hemolysin.
Bordetella pertussis adenylate cyclase-hemolysin (AC-Hly), encoded by the cyaA gene, belongs to the RTX family of toxins with extensive glycine-rich repeats in the carboxy-terminal portion. AC-Hly possesses both adenylate cyclase toxic and hemolytic activities that depend on a posttranslational modification mediated by the product of the cyaC gene. An improved system for AC-Hly synthesis and activation in Escherichia coli was developed. The results show that with purified AC-Hly (i) increased expression of the cyaC gene leads to a higher proportion of activated AC-Hly, (ii) the increase in protective activity of the activated recombinant AC-Hly correlates with the increase in its invasive and hemolytic activities, and (iii) the activated recombinant AC-Hly, but not the nonactivated recombinant AC-Hly, is a protective antigen against B. pertussis infection in a murine respiratory model. This suggests that possibly an immunodominant epitope required for protective activity is linked to the CyaC-mediated modification. Surprisingly, the protective and hemolytic activities of activated recombinant AC-Hly were lower than those of AC-Hly produced by B. pertussis, while its invasive activity was higher. This indicates that the modification of AC-Hly in B. pertussis and that in E. coli may differ.
Betsou
F
F
Unité de Bactériologie Moléculaire et Médicale, Institut Pasteur, Paris, France.
Sebo
P
P
Guiso
N
N
D000262:Adenylyl Cyclases / Q000235:genetics / Q000276:immunology / Q000633:toxicity*; D000818:Animals; D001483:Base Sequence; D001886:Bordetella pertussis / Q000235:genetics / Q000472:pathogenicity*; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D005798:Genes, Bacterial; D006460:Hemolysin Proteins / Q000235:genetics / Q000276:immunology / Q000633:toxicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000633:toxicity*; D014774:Virulence
D006460:Hemolysin Proteins; D011993:Recombinant Fusion Proteins; D000262:Adenylyl Cyclases