Antibodies to Proteases and Exotoxin A of Pseudomonas aeruginosa in Patients with Cystic Fibrosis: Demonstration by Radioimmunoassay

Abstract

Sera from 33 patients with cystic fibrosis and two pediatric patients being treated for chronic pulmonary infections not related to cystic fibrosis and six sera or serum pools from uninfected individuals were tested with a microtiter radioimmunoassay for reactivity against exotoxin A and two proteases from Pseudomonas aeruginosa. Exotoxin A was purified from a low-protease strain of P. aeruginosa and shown to have adenosine diphosphate-ribose transferase activity and mouse lethality. Proteases were purified from an isolate of P. aeruginosa from a patient with cystic fibrosis and had proteolytic activity against elastin and collagen in an assay employing dimethylated protein substrates. The antibody responses of the patients detected using 125I-labeled antibody to human immunoglobulin were correlated with clinical evaluations expressed as a composite score based on pulmonary findings, case histories, growth and nutrition, and chest X rays. Values in the radioimmunoassay for patients' sera were compared with those of a control serum pool and expressed as the ratio of counts per minute (cpm) in patient serum to the cpm in the control pool. Inverse correlations were found between these ratios for each of the pseudomonas exoproducts and clinical scores; highest ratios occurred in patients showing the lowest clinical scores. These results confirm that proteases and exotoxin A of P. aeruginosa are produced in cystic fibrosis pulmonary infections due to P. aeruginosa and suggest that they may serve as significant virulence factors in these chronic infectious states.

Active Immunization with Lipopolysaccharide Pseudomonas Antigen for Chronic Pseudomonas Bronchopneumonia in Guinea Pigs

“…The statistical analysis for the differences in cfu per milliliter lung was repeated, using cfu values expressed as log,0. (5,8,11). Additionally, in vitro studies have established that specific Pseudomonas antibodies enhance the bactericidal efficiency of phagocytic cells (10,32,33).…”

“…Whether the polyvalent LPS vaccine used in this study, or newer and potentially less toxic cell wall preparations (19,36), would be best suited for clinical use is unknown. Finally, whether the addition of toxoid materials derived from Pseudomonas exotoxin A or protease (11,36) might further protect the CF patient should be considered.…”

“…First, chronically infected CF patients have permanent lung damage and it may be impossible to arrest or reverse the disease at this stage (1)(2)(3)8). Second, chronically infected CF patients routinely develop elevations in Pseudomonas antibodies that appear inadequate to eradicate localized Pseudomonas infections in the lung (5)(6)(7)(8)11). Thus, further elevations in humoral antibody, raised by active immunization, might not offer benefit.…”

Immunoenzymometric Assays for Alkaline Protease and Exotoxin A from Pseudomonas aeruginosa: Development and Use in Detecting Exoproteins in Clinical Isolates from Patients with Cystic Fibrosis

“…production (2-4). These enzymes have been implicated äs important factors contribüting directly or indirectly to the pathogemicity of tliis mieroorganism in lung diseases (5)(6)(7)(8)(9)(10). Patients with cystic fibrosis have a high prevalence of Pseudomonas aeruginosa colonization, which rapidly causes a chronic infection of the mucosal surface of the 1 ) Funding organisations: Association Frangaise de Lutte contre la Mueoviscidose (AFLM), and Commission Scientifique de la Recherche des Hospices Civils de Lyon.…”

Pseudomonas aeruginosa infection and vaccination in the rat

“…Although antitoxin neutralises cytotoxity in vitro (Leppla, 1976), the manifestations of pseudomonas infection cannot all be ascribed to toxin, and antitoxin does not protect from a lethal challenge (Snell et al, 1978;Stieritz and Holder, 1978). High antibody levels to exotoxin A and proteases in cystic fibrosis patients were directly related to the severity of the disease (Klinger et al, 1978). Pseudomonas slime consists of high molecular-weight polysaccharides (Evans and Linker, 1973) and is more toxic than LPS; it produces leucopenia and death.…”