Human anti-Pseudomonas aeruginosa outer membrane proteins IgG cross-protective against infection with heterologous immunotype strains of P-aeruginosa

In order to develop an effective means to treat and prevent Pseudomonas aer uginosa infections, we have purified P. aeruginosa outer membrane protein ( Oprs)-specific human IgG antibody using a large-scale affinity column. In t his study, we investigated the cross-protective activity of the purified an ti-Oprs IgG against various immunotype strains of P. aeruginosa. The anti-O prs IgG reacted with Oprs isolated from seven Fisher-Devlin immunotype stra ins of P. aeruginosa and was able to promote opsonophagocytic killing of al l seven immunotype strains by human phagocytic cells. Administration of 500 mu g anti-Oprs IgG to mice raised the LD50 of the P. aeruginosa strains by 8-250-fold, indicating the protective capacity against heterologous P. aer uginosa strains as well as homologous strains. In contrast, despite high ti ters against P. aeruginosa Oprs, total serum IgG isolated from burn patient sera was no better than normal serum IgG in protecting mice from infection with P. aeruginosa. These data demonstrate that the affinity-purified huma n anti-Oprs IgG could afford protection against heterologous immunotype P. aeruginosa strains and provide a rationale to use anti-Oprs IgG as an adjun ct for treatment of P. aeruginosa infections in humans. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.