Chemical Synthesis of Acetobacter pasteurianus Lipid A with a Unique Tetrasaccharide Backbone and Evaluation of Its Immunological Functions
摘要:
Lipopolysaccharide (LPS), a cell surface component of Gram‐negative bacteria, activates innate immunity. Its active principle is the terminal glycolipid lipid A. Acetobacter pasteurianus is a Gram‐negative bacterium used in the fermentation of traditional Japanese black rice vinegar (kurozu). In this study, we focused on A. pasteurianus lipid A, which is a potential immunostimulatory component of kurozu. The active principle structure of A. pasteurianus lipid A has not yet been identified. Herein, we first systematically synthesized three types of A. pasteurianus lipid As containing a common and unique tetrasaccharide backbone. We developed an efficient method for constructing the 2‐trehalosamine skeleton utilizing borinic acid‐catalyzed glycosylation to afford 1,1’‐α,α‐glycoside in high yield and stereoselectivity. A common tetrasaccharide intermediate with an orthogonal protecting group pattern was constructed via [2+2] glycosylation. After introducing various fatty acids, all protecting groups were removed to achieve the first chemical synthesis of three distinct types of A. pasteurianus lipid As. After evaluating their immunological function using both human and murine cell lines, we identified the active principles of A. pasteurianus LPS. We also found the unique anomeric structure of A. pasteurianus lipid A contributes to its high chemical stability.
Stereoselective Synthesis of Sialyl Lewis<sup>a</sup> Antigen and the Effective Anticancer Activity of Its Bacteriophage Qβ Conjugate as an Anticancer Vaccine
作者:Zahra Rashidijahanabad、Sherif Ramadan、Nicholas A. O'Brien、Athar Nakisa、Shuyao Lang、Howard Crawford、Jeffrey C. Gildersleeve、Xuefei Huang
DOI:10.1002/anie.202309744
日期:2023.11.20
develop an effective sialyl Lewisa based vaccine, the stereoselective synthesis of sialyl Lewisa tetrasaccharide was accomplished. The glycan was covalently conjugated with a powerful carrier, bacteriophageQβ, which induced higher levels of and persistent anti-sialyl Lewisa IgG antibody responses, thus providing significant tumor protection in a metastatic cancer model in mice.