Chapter 16 - Bordetella protein toxins

Abstract

This chapter reviews the genus of Bordetella, whichproduces non-protein toxins, such as endotoxin or lipopolysaccharide and tracheal cytotoxin. These toxins may sometimes act in synergy with the protein toxins. The three major protein toxins are pertussis toxin, adenylate cyclase, and dermonecrotic toxin, which are also reviewed. Pertussis toxin (PTX) is the most complex soluble bacterial exo-protein known to date. PTX expresses a wide variety of different biological activities. They include the induction of morphological changes of target cells, of exocrine secretion, of the stimulation of lipolysis, the activation of pancreatic islet cells, histamine sensitization, the induction of lymphocytosis, and many others. The adenylate cyclase (ACT, AC-Hly, or CyaA) is the only known enzyme toxin capable of directly penetrating target cells across the cytoplasmic membrane and of reaching the cytosol without the need for endocytosis. The role of CyaA in the interaction of Bordetella with the cells of the respiratory epithelia and in the modulation of the host immune response through induction of proinflammatory cytokine secretion remains poorly explored. Dermonecrotic toxin (DNT) is an intracellular toxin. The role of the B. hronchiseptica DNT in the pathogenesis of respiratory disease in swine has more recently been firmly established by the use of isogenic strains only differing in the production of DNT.