Immunization with an Induced Avirulent Auxotrophic Mutant of Pseudomonas Pseudomallei

Abstract

A virulent strain of Pseudomonas pseudomallei was subjected to ultraviolet irradiation and a mutant clone requiring preformed adenine or hypoxanthine for growth was isolated. The imposition of auxotrophism was associated with a striking decline in virulence for mice which could be restored by permitting the strain to revert to purine independence in vitro. The mutant persisted in mice without detected reversions or or untoward effects for approximately 20 days following inoculation of 107 cells. After repeated inoculations, a significant immune response was demonstrated by parenteral challenge with diverse strains of this species. However, animals so immunized remained susceptible to lethal respiratory infection.