Abstract

Salmonella typhimurium is an intracellular pathogen that predominantly induces cell-mediated immunity. Quercetin is a naturally occurring flavonoid has been widely studied due to its immunomodulatory activity. The present study investigates the effects of quercetin on immune responses initiated by killed whole cell sonicated antigen from Salmonella typhimurium (KWCSA-ST) in mice. Twenty-four mice were randomly divided into four groups: control group, quercetin-treated (100 mg/kg), KWCSA-ST and combined treatment group (quercetin + KWCSA-ST). Interferon gamma (IFN-γ) was quantified by ELISA at days 10,14 and 21. On day 21, significantly elevated IFN-γ levels were observed in combined group with 186.34 ± 5.35 ng/ml. The values recorded in the quercetin group (113.60 ± 7.26 ng/ml), KWCSA-ST group (83±1.04ng/ml) and control group showed lower levels compared with treated groups. Histopathological evaluation showed normal tissue architecture was present in controls and mild immune-related changes were identified within the quercetin group. The inflammatory changes in the KWCSA-ST group were moderate. In contrast, the immune activity of combined group including intestinal mucosal hyperplasia; infiltration with inflammatory cells in liver but no necrosis' and increased expansion of splenic white pulp was more evident. In conclusion and significance overall, quercetin exhibited a synergistic immunomodulatory effect with KWCSA-ST enhanced antigen-induced immune responses without apparent tissue damage.