Cross‐Reactions between Pseudomonas aeruginosa and Thirty‐Six Other Bacterial Species

Cross‐reactions between Pseudomonas aeruginosa and 36 other bacterial species were studied by various quantitative immunoelectrophoretic techniques. A complex Pseudomonas aeruginosa antigen and a corresponding rabbit antiserum were used as a reference system. Ten of the 55 Pseudomonas aeruginosa antigens were cross‐reactive with antigens from as many as 33 other bacterial species, gram‐negative as well as gram‐positive. As judged by absorption of antibodies the degree of cross‐reactivity of each of the 10 Pseudomonas aeruginosa antigens with antigens from other species was found to be 25–100%, depending on the species and the antigen in question. The closest antigenic relationship to Pseudomonas aeruginosa was found in 5 other Pseudomonas species, but members of the Enterobacteriaceae also cross‐reacted fairly extensively with Pseudomonas aeruginosa. One of the cross‐reactive antigens reacted with a normally occurring antibody in sera from rabbits.