The serology of Pseudomonas aeruginosa analysed by means of quantitative immunoelectrophoretic methods. II. Comparison of the antibody response in man against thirteen O groups of Ps. aeruginosa.

The occurrence of antibodies against antigens prepared from strains representing 13 O groups of Pseudomonas aeruginosa and against a polyvalent Ps. aeruginosa antigen (St-Ag) has been investigated in sera from 100 patients. By means of fused rocket immunoelectrophoresis with intermediate gel it was found that the humoral immune response against Ps. aeruginosa resulting in precipitating antibodies will be detected by St-Ag as well as by any other of the antigen samples investigated. Six of the sera contained group-specific antibodies which were revealed by only one of the antigen samples used and not by St-Ag. These six sera were further studied by means of various quantitative immunoelectrophoretic methods using St-Ag as well as antigens prepared from the infecting Ps. aeruginosa strain in the patient concerned. In all six sera, only one extra precipitin could be detected using antigens prepared from the homologous strain instead of St-Ag. This extra precipitin corresponded presumably to group-specific O-antigens not included in St-Ag. In sera from patients, these group-specific antibodies were always accompanied by antibodies against antigens common to all strains of Ps. aeruginosa.