| Abstract: | The protective properties of formulated toxoid obtained from the highly purified preparation of P. aeruginosa exotoxin A have been studied in the test of the active immunization of mice. The study has revealed that the preparation when introduced in 1 or 2 injections in a dose of 15 micrograms, shows faint protective potency with respect to P. aeruginosa strains differing in virulence. Immunization with this toxoid in 3 and 4 injections has been found to ensure 60-100% and 50-60% protection of mice infected with P. aeruginosa toxigenic and proteolytic strains respectively. Immunization with toxoid has been found to induce the appearance of short-term antibacterial immunity which loses its capacity to protect the immunized animals, challenged with both toxigenic and proteolytic P. aeruginosa strains, as early as on day 28. The immunization of mice with toxoid in 4 injections has been shown to induce the development of antitoxic immunity capable of neutralizing up to 150 LD50 of purified exotoxin A. |
