Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: February 22, 1999
Publication Date: N/A
Technical Abstract: Members of the genus Bordetella cause upper respiratory infections in a number of animal species. While these organisms produce a number of virulence factors, only endotoxin, tracheal cytotoxin, and dermonecrotic toxin (DNT) are common to all pathogenic Bordetella species. The role of DNT in the pathogenesis of Bordetella infections has yet to be elucidated. In the present study, DNT was purified from Bordetella avium. B. avium DN had an isoelectric point in the range of pH 6.3-6.7 and a molecular size of approximately 155 kDa. Mice were given an intraperitoneal injection of one of several doses of purified DNT. Tissue samples from mice were collected for histopathological evaluation. The most remarkable lesions were seen in lymphoid tissues, including spleen, thymus, mesenteric lymph node (MLN), and ileal Peyer's patches (PP). In the spleen, there was evidence of increased numbers of hematopoietic cell foci. MLN and PP had prominent germinal centers primarily composed of lymphoblasts; some PP contained moderate numbers of mitotic figures. In addition, there was a moderate to marked necrosis in splenic white pulp, thymic cortex, MLN, and PP characterized by discreet multifocal accumulations of pyknotic cells and cellular debris. The observed appearance of lymphoblasts concurrent with pyknotic cells in some lymphoid tissues following DNT administration may represent an attempt by the host to compensate for the increased loss of lymphocytes. The lymphoid alterations observed in the present studies indicate that Bordetella DNT could compromise the host immune response.