The present invention relates to an immune response regulatory substance having a novel structure, and an immunologic adjuvant composition containing the same and, more specifically, to an immune response regulatory substance, which is a lipopolysaccharide (LPS) analog having reduced toxicity, and a use thereof. The immune response regulatory substance of the present invention exhibits immune enhancement effects by having excellent innate immunity and ability to induce an adaptive immune response to a specific pathogen, and is very safe by having lox toxicity. In addition, a vaccine containing the immune response regulatory substance of the present invention contains both an immune response regulatory substance and an alum, thereby improving immune enhancement effects compared with when using only the immune response regulatory substance.
