Prophylaxis of Pseudomonas aeruginosa infections in leukopenic mice by a combination of active and passive immunization.

Mice rendered leukopenic with cyclophosphamide and then challenged with viable Pseudomonas aeruginosa were used to determine the protective efficacy of active immunization against exotoxin A and of passive immunization with human antiserum to Escherichia coli J5, a rough mutant of Escherichia coli O111:B4. Neither treatment alone provided a greater degree of protection than its respective control. However, the combination of these treatments produced a moderate, yet consistent, increase in the survival of infected immunosuppressed mice.