in vivo Evaluation of Immunomodulatory Activity of Lipopolysaccharide Zinc Oxide Nanoparticles (LPS-ZnNPS)

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 ۷۵% of the surface area and ۵-۱۰% 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 ۳۵, Balb/c mouse was injected intramuscularly (i.m.) with different concentrations of the purified LPS, ZnoNPs and LPS-ZnoNPs for ۱۲ days and immunized with ۱۰% SRBCs (i.p) on day ۴ and ۸ 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-۲, IL۱Beta, IL۴, and IL۱۰) using sandwich ELISA. The data showed the highest value before and after treatment with LPS-ZnO NPs recorded in ۲µg/mouse was ۲۷. ۹۲±۱.۴۸ and ۳۱.۵۰±۰.۴, respectively. In Arthurs reaction and Delayed type hypersensitivity, the highest results showed in the positive control group injected with K. pneumoniae ۴.۰۸±۰.۱۷ and ۴.۸۶±۸۰.۰۲, respectively. The results of TLR-۲ showed the highest value in the positive control group, ۲۴۲.۱۷±۳.۹۸ pg/ml, followed by Group LPS at ۱۳۵.۵۱.۵۸ pg/ml. The results of Interleukin-۱Beta showed the highest value in the positive control group, ۲۵۴.۸۸±۳.۵۱ pg/ml, followed by Group LPS ۱۷۴.۳± ۱.۴۶ pg/ml. The concentration of IL-۴ in serum of treated albino mice showed the highest value in the positive control group, ۱۳۶.۲±۱.۱۲ pg/ml, followed by Group LPS ۸۶.۱۲±۱.۴۹ pg/ml. While the highest value of IL-۱۰ was recorded in the positive control group, ۹۸.۵۸± ۴.۰۹ pg/ml, followed by Group LPS- ZnoNP in concentration ۴µg/ mouse was ۸۶.۰۱۸±۰.۶۹ pg/ml. The results of the statistical analysis showed a significant difference (P≤۰.۰۵) 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-۱ beta, IL-۴, IL-۱۰, and TLRs-۲, Abs titer, and Arthus and DTH reactions.

Keywords:

K. pneumoniae , LPS- ZnO NPs , Arthus , DTH Reactions , Cytokines , TLR-۲