Vaccines against Pseudomonas aeruginosa infection: 1. Experimental studies.

An experimental study of several types of vaccines against Pseudomonas aeruginosa has been carried out. Pyoimmunogen, a multi-component vaccine consisting mainly of heat-stable proteins (or polypeptides) with a molecular weight of 20 000 to 60 000, was prepared both by laboratory and production techniques using three or five selected strains of P. aeruginosa. The preparations obtained by both methods were found to be of low toxicity and to induce in mice and rats active immunity against challenge with homologous and some heterologous strains of P. aeruginosa, including the toxigenic PA-103 strain. The Pseudomonas vaccine (PV) was prepared from partly purified water-soluble protein antigens (molecular weight ranging from 10 000 to 100 000) obtained from one (mono-PV) or three (tri-PV) selected strains. Mono-PV was prepared by the method of ultrafiltration and tri-PV--by differential centrifugtion. Both types of vaccines proved effective in active mouse protection tests after challenge with homologous as well as with heterologous P. aeruginosa strains. Mono-PV is supposed to induce species-specific immunity against P. aeruginosa infection in mice.