Protection Against Infection with Pseudomonas Aeruginosa by Passive Transfer of Monoclonal Antibodies to Lipopolysaccharides and Outer Membrane Proteins

Experimental infection with Pseudomonas aeruginosa was treated with eight different monoclonal antibodies (MCAs) produced by hybridoma cells obtained through cell fusion of mouse plasmacytoma cells and spleen cells from mice immunized with a virulent strain of P. aeruginosa (Homma serotype 7). Five MCAs bound to lipopolysaccharides (LPSs) specific to serotype 7 or serotypes 2, 7, and 13, whereas the other three MCAs bound with broad specificities to outer membrane protein (OMP) fractions. The MCAs to LPS were highly protective against infection, with 50% protective doses of 0.05-2.5 micrograms of immunoglobulin per mouse. In contrast, the MCAs to OMP were much less protective, with a 50% protective dose range of 10 to greater than 100 micrograms of immunoglobulin per mouse. Most of the MCAs to LPS agglutinated P. aeruginosa cells, but all the MCAs to OMP produced so far have not, although all the MCAs bound well to the cells. Agglutinating MCAs provided better protection than did nonagglutinating MCAs.