Conformation-dependent antibody response to Pseudomonas aeruginosa outer membrane proteins induced by immunization in humans

Outer membrane proteins (OMPs) of pathogenic bacteria have been used as pro tective antigens in developing bacterial vaccines. In the present study, we compared the antibody responses to a Pseudomonas aeruginosa OMP Vaccine el icited in humans and rabbits by immunization. Immunization with the vaccine induced high titers of serum IgG antibody both in rabbits and humans but r eactivities of the induced antibodies with the OMPs were different. The rab bit immune sera recognized most of the OMPs in the Vaccine both in immunobl ot and immunoprecipitation analyses. In contrast, a great variation in band pattern and intensity was observed among the human immune sera in immunobl ot analysis, but not in immunoprecipitation analysis. Denaturation of the O MPs did not affect the binding activity of the rabbit immune sera as determ ined by ELISA, but substantially reduced those of the human immune sera and anti-OMP IgG purified from a pooled normal human plasma. These data sugges t that antibody response to P. aeruginosa OMPs elicited by immunization in humans is mainly directed against discontinuous or conformation-dependent e pitopes, which should be taken into account in developing vaccines, especia lly for OMP-derived synthetic peptides. (C) 2000 Federation of European Mic robiological Societies. published by Elsevier Science B.V. All rights reser ved.