Antibody responses in serum against P. aeruginosa antigens when measured on day 28. In view of the above findings, the purpose of this work was to study whether antibodies induced by the vaccines P. aeruginosa whole cell sonicate, O PS toxin A conjugate, an alginate toxin A conjugate, O PS toxin A conjugate plus ARRY-142886 alginate toxin A conjugate, or native alginate could prevent chronic lung inflammation or minimize the inflammatory response which in CF is dominated by PMNs, when given subcutaneously before challenge with P. aeruginosa in alginate beads in our rat model of chronic P. aeruginosa lung infection. Since PMN elastase plays such a crucial role in the tissue damage in lungs of CF patients, prevention of PMN dominated inflammation might be of great advantage. MATERMILS AND METHODS Animals.
Seven week old female Sprague Dawley rats in groups of 20 to 46 weighing approximately 170 g were used. Challenge strain. P. aeruginosa PAO 579, which stably maintains a mucoid phenotype and is International Antigenic Typing System 0:2/5, was used. Ki16425 The behavior of this strain in the chronic infection model has been previously described. Immobilization of P. aeruginosa in spherical alginate beads. Briefly, 1 ml of the P. aeruginosa bacterial culture was mixed with 9 ml of seaweed alginate and forced once with air through a cannula into a solution of 0. 1 M CaCl2 in 0. 1 M TRIS HCI buffer. The suspension was adjusted to yield 109 CFU/ml and confirmed by colony counts. Vaccines. We used the following control and vaccine groups. Controls consisted of 0. 1 ml of 0. 15 M sterile NaCl and 0.
1 ml of incomplete Freund,s adjuvant. Vaccines consisted of sonicated P. aeruginosa PAO 579, with a protein concentration of the antigen preparation of 19. 7 g/liter, P. aeruginosa O PS toxin A, depolymerized P. aeruginosa alginate covalently coupled to toxin A, 0. 25 ml of O PS toxin A plus 0. 25 ml of D ALG toxin A, and purified alginates from P. aeruginosa 6680 and 8839 mixed with IFA. Vaccines used in vaccine groups to were adsorbed to Al3, whereas the vaccines in control group and vaccine groups and were mixed with IFA. Immunization and challenge procedures. On days 0 and 14, each of the seven groups of rats were subcutaneously immunized with one of the above mentioned vaccines. On day 28 all rats were intratracheally challenged with 0. 1 ml of P. aeruginosa in alginate beads.
Blood samples. On day 0, blood was drawn from 20 randomly chosen rats, and this pool was used as reference day 0 pool in all the enzyme linked immunosorbent assays. On day 28, 1. 5 ml of blood was drawn from the right orbital plexus from all rats as previously described. All animals were sacrificed on day 56. Macroscopic description of the lungs. After removal, all lungs were macroscopically assigned to one of four groups, according to the severity of the infection: 1, normal, 2, swollen lungs, hyperemia, small atelectasis, 3, adherences, small hemorrhages, small abscesses, atelectasis, 4, adherences, hemorrhages, abscesses, and atelectasis. The scoring was performed in a blinded fashion to avoid bias. Histopathologic testing. Lungs from 10 to 36 animals in each group were prepared for histologic examination. The lower section of the left lung lobe was fixed in formalin, embedded in paraffin wax
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