A new assay for the invasive adenylate cyclase toxin of Bordetella pertussis based on its morphological effects on the fibronectinstimulated spreading of BHK21 cells

• Published in: Microbiology (Society for General Microbiology) Vol. 140; no. 2; pp. 245 - 253
• Main Authors: Westrop, G. D, Campbell, G, Kazi, Y, Billcliffe, B, Coote, J. G, Parton, R, Freer, J. H, Edwards, J. G
• Format: Journal Article
• Language: English
• Published: Soc General Microbiol 01.02.1994
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-140-2-245

Departments of Microbiology, University of Glasgow, Glasgow G12 8QQ, UK Cell Biology, University of Glasgow, Glasgow GI2 8QQ, UK ABSTRACT Summary: When baby hamster kidney (BHK) cells are allowed to spread on fibronectincoated substrata in the absence of serum and the presence of agents which elevate intracellular 3‘:5‘-cyclic AMP (cAMP) levels they adopt an abnormal, stellated morphology. To determine whether the invasive adenylate cyclase (AC) toxin of Bordetella pertussis induced the same response, cell extracts were prepared from several B. pertussis strains. They were characterized for AC toxin production by enzymic assay and by immunobiotting with an AC-toxin-specific monoclonal antibody. Extracts of strains producing AC toxin induced elevated levels of intracellular cAMP in BHK cells and promoted a stellation response during cell spreading. Extracts prepared from strains defective in AC toxin production showed no effect. Using image analysis to quantify the morphological change, we have demonstrated that the effect of AC toxin on cell spreading is dose dependent. This technique is a rapid and sensitive assay for the invasive AC toxin. Author for correspondence: G. D. Westrop. Tel: +44 41 339 8855 ext. 5840. Fax: +44 41 330 4600. Keywords: Bordetella pertussis , adenylate cyclase toxin, fibroblast, cell shape Present address: Shah Abdul Latif University, Khairpur Mirs, Sindh, Pakistan.