Sulfated lactosyl archaeol (SLA) archaeosomes as a vaccine adjuvant

Archaeosomes are liposomes traditionally comprised of total polar lipids or semi-synthetic glycerolipids of ether-linked isoprenoid phytanyl cores with varied glycol- and amino-head groups. We have developed a semi-synthetic archaeosome formulation based on sulfated lactosylarchaeol (SLA) that can be readily synthesized and easily formulated to induce robust humoral and cell-mediated immunity following systemic immunization, enhancing protection in models of infectious disease and cancer. Liposomes composed of SLA have been shown to be a safe and effective vaccine adjuvant to a multitude of antigens in preclinical studies including hepatitis C virus E1/E2 glycoproteins, hepatitis B surface antigen, influenza hemagglutinin, Rabbit Hemorrhagic Disease Virus antigens, and SARS-CoV-2 Spike antigens based on the ancestral strain as well as multiple variants of concern. With the COVID-19 pandemic highlighting the need for new vaccine technologies including adjuvants, this review outlines the studies conducted to date to support the development of SLA archaeosomes as a vaccine adjuvant.