Enhancement of antigen-specific immunity via the TLR4 ligands MPL adjuvant and Ribi.529

MPL (Corixa) Adjuvant is a chemically modified derivative of lipopolysaccharide that displays greatly reduced toxicity while maintaining most of the immunostimulatory activity of lipopolysaccharide. MPL Adjuvant has been used extensively in clinical trials as a component in prophylactic and therapeutic vaccines targeting infectious disease, Cancer and allergies. With over 33,000 doses administered to date, MPL Adjuvant has emerged as a safe and effective vaccine Adjuvant. Recently, scientists at Corixa Corporation have developed a library of synthetic lipid A mimetics (aminoalkyl glucosaminide 4-phosphates) with demonstrated immunostimulatory properties. Similar to MPL Adjuvant, these synthetic compounds signal through Toll-like Receptor 4 to stimulate the innate immune system. One of these compounds, Ribi.529 (RC-529), has emerged as a leading Adjuvant with a similar efficacy and safety profile to MPL Adjuvant in both preclinical and clinical studies.