An assay for measuring specific adhesion of anEscherichia coli strain to tissue culture cells

Abstract

Escherichia coli SS142 has been found to adhere specifically to the human epithelioid tissue culture cell line Intestine 407, but not to other tissue culture cells. This paper describes an accurate, reproducible and objective method of assessing the rate of adhesion of radiolabelled bacteria to these cellular monolayers. Adhesion was found to be linear with time for 60 min and with bacterial concentrations up to 10⁹ bacteria/ml. The binding appeared to be irreversible. Adhesion was not affected by changes in the composition of the medium, its pH or ionic strength, or by the assay temperature within physiological limits, but was diminished at very high ionic strength or low temperature. It increased with increasing cell density of the monolayers. Under appropriate conditions the assay could be used for comparative determinations of the rate of adhesion of different, or differently treated bacteria.