combined glycyrrhizic acid and alum liposomes enhance immune response to inactivated salmonella typhimurium

Killed microorganisms combined with alum typically do not elicit strong cellular immune responses. glycyrrhizic acid, a triterpenoid saponin, possesses immunomodulatory properties. this study investigated the synergistic effects of glycyrrhizic acid (gl) and alum liposomes on immune responses against heat-killed salmonella typhimurium (hkst). in this experimental study, male balb/c mice were divided into 5 groups of 15 and immunized with hkst vaccine alone or in combination with alum, gl, or alum-gl combination twice, with a two-week interval. fourteen days post-last vaccination, immune responses against s. typhimurium and the protective potential of the vaccines were evaluated. survival rate was monitored using kaplan-meier analysis. other findings were analyzed via one-way analysis of variance and tukey s post hoc test, with significance set at p<0.05. the group receiving combined adjuvant and hkst showed significant increases in delayed-type hypersensitivity reaction, lymphocyte proliferation, igg2a antibody titer, and improved survival against live challenge compared to other groups. furthermore, the combined adjuvant group exhibited a more pronounced increase in ifn-γ levels and decrease in il-4 levels than the other groups. the alum-gl combination, used as an adjuvant, synergistically enhanced cellular and humoral immunity following immunization with the hkst vaccine.