The Journal of Medical Microbiology, Vol 48, Issue 7 637-648, Copyright © 1999 by Society for General Microbiology
Bactericidal activity of rat lung lavage fluid against Bordetella pertussis
G. N. Al-Fellah, R. Parton and A. C. Wardlaw
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow.
Cell-free lung lavage fluid (LLF) from healthy normal rats killed phase I
(wild-type, virulent) Bordetella pertussis at 37 degrees C in vitro. B.
parapertussis was also killed by the LLF, but phase IV (avirulent mutant)
B. pertussis and some other common bacterial species, including B.
bronchiseptica, were not. Transmission electron microscopy of thin sections
of the phase I B. pertussis showed extensive structural damage and cell
lysis. None of the other mammalian species tested had LLF with bactericidal
activity against B. pertussis as high as that of the rat. Rats killed with
halothane yielded LLF with higher bactericidal activity than when CO2 was
used. Ultracentrifugation of LLF at 55,000 g gave a surfactant (pellet)
fraction that had c. 95% of the bactericidal activity and which was
biochemically distinct from the 5% of activity in the supernate fraction.
Phospholipids and fatty acids appeared to be involved in LLF bactericidal
activity, but not complement or lysozyme. Arachidonic acid was the most
active of the fatty acids tested. Artificial surfactant, as used in
premature infants, had no bactericidal effect on B. pertussis.
