An adjuvant is a substance that is added to a vaccine to boost the immune response, thus minimizing the dose of antigen needed. Since pandemic situations lead to vaccine shortages, decreasing antigen dose by the addition of adjuvants is important for ensuring a stable vaccine supply at a low cost. Therefore, academic research institutes and pharmaceutical companies invest a lot of effort and money to develop safe and effective adjuvants.

GLA is a derivative of the monophosphoryl lipid A (MPL, GSK Biologicals), a detoxificated form of lipopolysaccharide (LPS). It functions as a Toll-Like Receptor 4 (TLR4) agonist, efficiently inducing the Th1-mediated immune response. The Quratis inc. formulates GLA in an oil-in-water emulsion containing squalene to increase stability, homogeneity, and potency.

Intramuscular immunization with GLA-SE-formulated antigen induces recruitment of innate immune cells (antigen presenting cells) to the site of injection, some of which process the antigen and deliver it to the draining lymph nodes to induce specific adaptive humoral and cellular immune responses.