eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2024-12-30 17 4 2717 2728 10.13005/bpj/3061 63166 article Namir I. Mohammed 1 Ahmed Q. Al-Awadi 1 Department of Pathology and Poultry, Disease College of Veterinary Medicine / University of Baghdad, Baghdad, Iraq This study evaluated zinc oxide nanoparticles (ZnO-NPs) as immunological adjuvants against Staphylococcus lugdunensis. Fifty male rats (8–10 weeks old) were divided into five groups. Group 1 received sterile saline (negative control), Group 2 was infected with S. lugdunensis (positive control), Group 3 was immunized with sonicated S. lugdunensis antigens, Group 4 received sonicated antigens loaded on ZnO-NPs, and Group 5 received ZnO-NPs only. Serum levels of IL-10 and IgG were measured 28 days post-immunization, and internal organs (heart, kidney, and lung) were examined histopathologically at 7 and 21 days post-infection. Groups immunized with antigens (Groups 3 and 4) showed significantly higher IL-10 and IgG levels compared to controls. Histopathological findings revealed severe vascular congestion in the heart, mild glomerular atrophy with edema in the kidney, and lung hemorrhages in infected groups, while granulomatous lesions were only found in Groups 2 and 3. Immunization with sonicated antigens alone or combined with ZnO-NPs improved immune response and reduced tissue damage. The most effective immune stimulation and protection were observed in the group receiving ZnO-NP-loaded antigens, demonstrating their potential as adjuvants to enhance immune defense and mitigate the effects of S. lugdunensis infection. https://biomedpharmajournal.org/vol17no4/potential-of-zinc-oxide-nanoparticle-as-adjuvant-therapy-against-staphylococcus-lugdunensis-by-modulating-immune-response/ Immune Response Sonicated Ag Staphylococcus lugdunensis ZnO-NPs