A possible association between CFA (I) fimbriae and K99 fimbriae on Escherichia coli and bacterial adherence to human lymphocytes.

We have explored a possible association between Escherichia coli binding to human lymphocytes and plasmid coded fimbriae on the bacterial surface. E. coli with or without the plasmid coded membrane CFA(I), K99 and K88 were mixed with freshly-drawn human peripheral blood lymphocytes. When the lymphocytes were mixed with E. coli possessing the CFA(I) fimbriae, 59% of the lymphocytes bound bacteria onto the surface, whereas only 22% of the lymphocytes bound the CFA(I)- derivative. The lymphocytes bound 53% and 56% of two K9+ strains, whereas 22% and 8% of the lymphocytes adhered the same strains without the K99 fimbriae. Twelve per cent and 7% of lymphocytes bound bacteria when the strain was K88+ or K88-, respectively. Likewise a low (8%) adherence to lymphocytes was found when the E. coli did not possess fimbriae or flagella.