Klebsiella pneumoniae causes a wide variety of infectious diseases. Lipopolysaccharide (LPS) is a large heat-stable polymer that is gram-negative bacteria's major outer membrane component, accounting for roughly 75% of the surface area and 5-10% of the total dry weight. Therefore the current in vivo study was carried out to investigate the immunomodulatory effect of purified lipopolysaccharide produced from local clinical Klebsiella pneumoniae isolates compared with ZnO-NPs and LPS-ZnO NPs. To do the experimental evaluations 35, Balb/c mouse was injected intramuscularly (i.m.) with different concentrations of the purified LPS, ZnoNPs and LPS-ZnoNPs for 12 days and immunized with 10% SRBCs (i.p) on day 4 and 8 of the schedule, while K. pneumoniae suspension and normal saline for positive and negative control groups. Focus on estimating body weight before and after treatment, Arthus and delayed-type hypersensitivity, and detecting serum level of cytokines (TLR-2, IL1Beta, IL4, and IL10) using sandwich ELISA. The data showed the highest value before and after treatment with LPS-ZnO NPs recorded in 2µg/mouse was 27. 92±1.48 and 31.50±0.4, respectively. In Arthurs reaction and Delayed type hypersensitivity, the highest results showed in the positive control group injected with K. pneumoniae 4.08±0.17 and 4.86±80.02, respectively. The results of TLR-2 showed the highest value in the positive control group, 242.17±3.98 pg/ml, followed by Group LPS at 135.51.58 pg/ml. The results of Interleukin-1Beta showed the highest value in the positive control group, 254.88±3.51 pg/ml, followed by Group LPS 174.3± 1.46 pg/ml. The concentration of IL-4 in serum of treated albino mice showed the highest value in the positive control group, 136.2±1.12 pg/ml, followed by Group LPS 86.12±1.49 pg/ml. While the highest value of IL-10 was recorded in the positive control group, 98.58± 4.09 pg/ml, followed by Group LPS- ZnoNP in concentration 4µg/ mouse was 86.018±0.69 pg/ml. The results of the statistical analysis showed a significant difference (P≤0.05) between LPS, ZnoNPs, and LPs-ZnoNPs treated groups and control groups (positive & negative). In the present study, we can conclude that LPS-ZnO NPs had a positive immunomodulatory effect on immune response in immunized mice. As shown in the results of the level of IL-1 beta, IL-4, IL-10, and TLRs-2, Abs titer, and Arthus and DTH reactions.
Keywords: Arthus; Cytokines; DTH Reactions; K. pneumonia; LPS- ZnO NPs; TLR-2.