Pili from enterotoxigenic Escherichia coli pathogenic for humans have been isolated by adsorption to the surface of erythrocytes followed by thermal elution. The pili are composed of two protein subunits with molecular weights of 13,100 and 12,500 as determined by sodium dodecyl sulfate-gel electrophoresis. These pili also bind to human buccal cells under temperature conditions (37 degrees C) which prevent the binding of these pili to the erythrocytes. Analogous temperature effects on binding have previously been observed with whole bacterial cells. This binding can be inhibited by antiserum prepared against the isolated pili.
