Development of Adjuvants Based on Parasitic and Symbiotic Bacterial Lipid A

Abstract

Lipopolysaccharide (LPS), a gram-negative bacterial outer membrane component, is a representative immunostimulant, with terminal glycolipid lipid A as its active principle. Immunostimulant LPS is a potential candidate for adjuvants. However, LPS is an endotoxin causing lethal sepsis. Thus, we need to minimize its toxicity before using it in vaccines. Based on the concept that there is a lipid A-mediated bacterial-host chemical ecology, parasitic and symbiotic bacterial LPS and lipid A which are predsicted to have low-toxicity immunomodulators as they have different LPS chemical structures due to co-evolution with the host, have been focused. Analyzing these LPS and lipid A functions has led to the elucidation of the molecular basis of the parasitic and symbiotic phenomena has been progressed as well as the development of low-toxicity adjuvant has been conducted. In this review, recent developments in related research are presented.