Effect of Pseudomonas aeruginosa lectins on phagocytosis of Escherichia coli strains by human polymorphonuclear leucocytes.

The D-galactosephilic lectin of Pseudomonas aeruginosa (PA-I) agglutinates cells of E. coli O86B7, while its other lectin (PA-II) agglutinates E. coli O128B12 cells. Both lectins react with human peripheral leucocytes. Exposure of the human leucocytes to either of the two Pseudomonas lectins was found to depress their phagocytic activity towards E. coli O86B7 and O128B12 strains, as well as towards E. coli B cells, which are not agglutinated by the lectins. However, coating the E. coli O86B7 and O128B12 cells, respectively, with PA-I and PA-II lectins increased their phagocytosis by untreated human leucocytes. Control experiments in which E. coli O86B7 and O128B12 cells were exposed to PA-II and PA-I, respectively, did not lead to any increase in their phagocytosis.