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A structural comparison of the total polar lipids from the human archaea Methanobrevibacter smithii and Methanosphaera stadtmanae and its relevance to the adjuvant activities of their liposomes

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1016/S1388-1981(99)00130-4
AuthorSearch for: 1; Search for: 1; Search for: 1; Search for: 1; Search for: 1; Search for: 1; Search for: 1
Affiliation
  1. National Research Council of Canada. NRC Institute for Biological Sciences
FormatText, Article
SubjectPolar lipid structure; Archaeosome; Liposome; Adjuvant; Human archaea; Methanobrevibacter smithii; Methanosphaera stadtmanae
Abstract
Mice were immunized with bovine serum albumin (BSA) entrapped within archaeosomes (i.e. liposomes) composed of the total polar lipids (TPL) from the two methanogenic archaea common to the human digestive tract. Methanobrevibacter smithii archaeosomes boosted serum anti-BSA antibody to titers comparable to those achieved with Freund's adjuvant, whereas Methanosphaera stadtmanae archaeosomes were relatively poor adjuvants. An explanation for this difference was sought by analysis of the polar lipid composition of each archaeobacterium. Fast atom bombardment mass spectrometry and NMR analyses of the purified lipids revealed a remarkable similarity in the ether lipid structures present in each TPL extract. However, the relative amounts of each lipid species varied dramatically. The phospholipid fraction in M. stadtmanae TPL was dominated by archaetidylinositol (50 mol% of TPL) and the glycolipid fraction by beta-Glcp-(1,6)-beta-Glcp-(1,1)-archaeol (36 mol%), whereas in M. smithii extracts, both caldarchaeol and archaeol lipids containing a phosphoserine head group were relatively abundant. Liposomes prepared from purified archaetidylinositol and from M. stadtmanae TPL supplemented with increasing amounts of phosphatidylserine elicited poor humoral responses to encapsulated BSA. A dramatic loss in the adjuvanticity of M. smithii archaeosomes was seen upon incorporation of 36 mol% of the uncharged lipid diglucosyl archaeol and, to a lesser extent, of 50 mol% of archaetidylinositol. Interestingly, the relative rates of uptake of M. smithii and M. stadtmanae archaeosomes by phagocytic cultures in vitro were similar. Thus, the lipid composition may influence archaeosome adjuvanticity, particularly a high diglucosyl archaeol and/or archaetidyl inositol content, resulting in a low adjuvant activity
Publication date
In
  • Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1440, no. 2-3 (22 September 1999): 275–288.
LanguageEnglish
NRC numberSPROTT1999
NRCC 42395
NPARC number9375050
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Record identifiercadf045e-1ba4-4c2b-bf99-3192c14a0113
Record created2009-07-10
Record modified2020-03-20
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