Flagellin b Shifting the Immune Response Against P. aeruginosa Respiratory Infections from Chronic to Cure State

. Pseudomonas aeruginosa had been studied widely due chronically invade and infect many patients especially those immuno-compromised such as patients with malignant or HIV infection. Also, increase the prevalence of MDR P. aeruginosa infection especially those chronic pulmonary infection that lead to increasing of morbidity and mortality rate. This study aimed to study the protection poten-cy provided by flagellin as a candidate vaccine against acute fatal respiratory XDR P. aeruginosa infec-tion in the animal model. Flagellin-a and flagellin-b were purified from P. aeruginosa MJ isolate and used to immunize the animals intranasal for six doses separated by one-week intervals between every two doses. After one week of completing the immunization, each group was divided into two groups (A1 & A2, B1 & B2, and C1 & C2). Groups (A2, B2, and C2) were infected intranasal by 2*107 CFU of spe-cific P. aeruginosa isolate in each nostril. After 24 h. blood samples were collected by heart puncture from all groups (with and without infection) and used directly for the immunological studies using flow cytometry techniques. The results of this study showed that flagellin-b more than the flagellin-a in the elevation of Th1 cells in the immunized groups while they decreased in the non-immunized group that indicate it is more efficient the activation of Th1 cells after respiratory infection with P. aeruginosa. While Flagellin-b elevate Th2 cells in the immunized groups less than Flagellin and less than the non-immunized before and after infection. All that lead to the decrease of IgG1/IgG2a ratios among flag-ellin-b-immunized groups (compared to the non-immunized groups) indicated that flagellin-b tendency to direct immune responses toward Th1 responses. The purified flagellin-b is efficient in shifting the im -mune response against XDR P. aeruginosa infection toward cure state rather chronic which consider es-sential in the eradication of these bacterial infections.