Efficacy of modified human immune serum globulin in the treatment of experimental murine infections with seven immunotypes of Pseudomonas aeruginosa.

Modified immune serum globulin, prepared from human immune serum globulin by a nonenzymatic method, is apparently safe for intravenous administration to humans. The efficacy of the preparation was determined in experimental murine infections with seven immunotypes of Pseudomonas aeruginosa. Intravenously administered 0.85 percent NaCl, 0.3 m glycine, and 10 percent human albumin did not protect against lethal pseudomonas infection, whereas modified immune serum globulin given by the same route did protect mice. In the mouse protection test, the mean dose of the preparation that saved 50 percent of mice infected with any of eight strains of P. aeruginosa was 480 mg/kg (range, 12-2,333 mg/kg). For five strains the 50 percent effective dose was smaller than 200 mg/kg. There was no correlation between the efficacy of modified immune serum globulin in the mouse protection test and titers of antibody, as determined by bacterial agglutination. Therapy of pseudomonas infection in mice with modified immune serum globulin was followed by a prompt and persistent decrease in the numbers of intraperitoneal bacteria. This finding is consistent with the interpretation that modified immune serum globulin acts primarily as an opsonin and not as an antitoxin. Modified immune serum globulin may prove to be useful in the treatment of human infections.