Protective activity of an intravenous immune globulin (human) enriched in antibody against lipopolysaccharide antigens of Pseudomonas aeruginosa.

Human plasmas containing naturally high levels of immunoglobulin G (IgG) to lipopolysaccharide antigens of Pseudomonas aeruginosa immunotypes 1, 2, 4, and 6 were identified by an enzyme-linked immunosorbent assay. The high titered plasmas were collected, pooled, and fractionated. Cohn fraction II IgG was prepared for intravenous infusion. The antibody titers in the hyperimmune intravenous immunoglobulin preparation were approximately fivefold higher against P. aeruginosa immunotypes 1, 2, 4, 5, and 6 and approximately twofold higher against immunotypes 3 and 7 than conventional intravenous immunoglobulin G. When tested for prophylaxis in burned mice, the protective doses 50 percent of Pseudomonas-intravenous immunoglobulin G were approximately fourfold less effective against immunotypes 1, 2, 4, and 7 and International Antigenic Typing System Serotypes (IATS), 8 (= immunotype 6) than conventional intravenous immunoglobulin G. Against immunotype 3 and 5, IATS 13, 15, and 16, both immunoglobulin preparations afforded similar levels of protection. In burned mice challenged with immunotypes 1 and 2 and not treated until 18 hours after infection, Pseudomonas-intravenous immunoglobulin G and tobramycin had synergistic activity in preventing death. Pseudomonas-intravenous immunoglobulin G also afforded significant protection to immunosuppressed mice challenged with immunotype 1. These data suggest that Pseudomonas-intravenous immunoglobulin G may be useful in prevention or treatment of P. aeruginosa infections in man.