The serology of Pseudomonas aeruginosa analysed by means of quantitative immunoelectrophoretic methods.

The conformity of the immunoprecipitate pattern obtained with a polyvalent Pseudomonas aeruginosa antigen (St-Ag) and different pools of a polyvalent, purified (IgG and IgA) rabbit antiserum (St-Ab) against St-Ag has been studied. Ten rabbits were immunized and bled every fifth week. Eight pools of St-Ab were produced during nearly four years. All the St-Ab pools were mutually compared by means of quantitative immuno-electrophoretic methods. All St-Ab pools were found to present St-Ag/St-Ab immunoprecipitate patterns which, qualitatively and quantitatively, were similar. None of the obtained immunoprecipitates between St-Ag and the pooled antisera disappeared during the procedures of purification of IgG and IgA. Quantitative and qualitative comparison of the polyvalent St-Ab pools ("titre") was made by counting the total number of immunoprecipitates obtained by St-Ag, followed by their identification, and by calculating the mean area of 12 selected and representative immunoprecipitate. The abilities of the rabbits to produce antibodies were found to vary individually. None of the rabbits produced precipitating antibodies against all the 64 known P. aeruginosa antigens in St-Ag. On the average, each of the rabbits lacked precipitating antibodies against 5 of the antigens. By pooling antisera from 3 rabbits out of 8 only 14 per cent of the possible combinations would contain detectable precipitins against all the known antigens of St-Ag.