Establishment of Stable Cell Lines Producing Anti‐Pseudomonas aeruginosa Monoclonal Antibodies and Their Protective Effects for the Infection in Mice

Human‐human hybridomas producing monoclonal antibodies (MoAbs) specific for five major serotypes of Pseudomonas aeruginosa were developed by fusing P. aeruginosa primed and Epstein‐Barr virus‐transformed cells with human myeloma P109 cells using polyethyleneglycol. The MoAbs which were produced by the hybridomas were protective against lethal intraperitoneal (i.p.) challenge of P. aeruginosa (10 LD50) in mice. The 50% effective dose (ED50) values of MoAbs ranged from 0.5 to 10.2 μg/mouse and were 26 to 240 times more protective than a commercial human IgG preparation. MoAb administration to mice promoted bacterial clearance in peritoneal cavity, and prevented bacterial invasion into blood in the way of increasing both the number of bacteria trapped by a macrophage and the ratio of macrophages that trapped bacteria. MoAbs also showed protective effects against lethal infection of P. aeruginosa in the mice which were decreased in polymorphonuclear cells (PMN) by cyclophosphamide (CY). All MoAbs showed serotype‐specific binding to the clinical isolates of P. aeruginosa as well as to the immunized strains. The hybridoma cell lines maintained their capacity to produce MoAb continuously for more than 12 months and produced 10 to 60 μg MoAbs per 106 cells in 24 hr. It is practicable to use these cell lines for large‐scale production of anti‐P. aeruginosa MoAbs and such MoAbs must be useful for the therapeutics of patients with P. aeruginosa infection.