The hemagglutinating activities of Pseudomonas aeruginosa lectins PA-IL and PA-IIL exhibit opposite temperature profiles due to different receptor types

The two Pseudomonas aeruginosa lectins PA-IL and PA-IIL, which are very sim ilar in subunit size, composition and properties, but differ in carbohydrat e specificity, were shown to exhibit opposite temperature profiles in hemag glutination tests. The galactophilic PA-IL, which interacts with the erythr ocyte I antigen (together with B or P system antigens), resembles Ii system -specific 'cold hemagglutinins' (including antibodies and lectins of animal s and plants) in low (4 degrees C) temperature optimum, while the hemagglut ination by the fucose- and mannose-binding PA-IIL (like that of antibodies and lectins which do not bind to these antigens) increases on raising the t emperature from 4 to 37 degrees C and even to 42 degrees C. The preferentia l production of both P. aeruginosa lectins at 28 degrees C and their much s tronger interaction with enzyme (protease or sialidase)-damaged cells, as w ell as the lower temperature optimum (4 degrees C) of PA-IL-binding to the host cells, may be associated with the saprophytic rather than parasitic de signation of this bacterium. (C) 1999 Federation of European Microbiologica l Societies. Published by Elsevier Science B.V. All rights reserved.