Precipitating antibody to antigens of Pseudomonas aeruginosa in chronic obstructive lung disease.

Two antigens designated Pseudomonas aeruginosa cytoplasmic antigen (P(1-5)) and P. aeruginosa cell wal antigen (PCW) were prepared by ultrasonic disintegration and hot phenol extraction of a smooth polyagglutinable strain of P. aeruginosa isolated from the respiratory tract. It was shown that P(1-5) and PCW are immunologically distinct, that P(1-5) is heat-labile while PCW contains a heat-stable component which stains positively for polysaccharide, is positive for endotoxin and cross-reacts with a cell wall antigen of Haemophilus influenzae prepared by hot phenol extraction. Both antigens were able to activate the alternate pathway for complement. A statistically significant number of patients with cystic fibrosis and bronchiectasis have precipitating antibody to that fraction of cytoplasmic antigen specific for P. aeruginosa (P(1-2)) and PCW compared to controls, whereas patients with asthma and chronic bronchitis do not. The use of both antigens increases the number of patients with antibody to P. aeruginosa. Radioactive immunodiffusion studies indicate that 80.8% of controls have precipitating antibody to PCW antigen and that antibody to it is IgG, IgA and IgM. These studies indicate that consideration should be given to PCW as well as P(1-5) in any consideration of the pathogenesis of P. aeruginosa in these conditions.