title: Quantitative analysis of a synthetic adjuvant by an immunoassay.
abstract: Antibodies against a sulpholipo-derivative of synthetic polysucrose (SL-Ficoll) were prepared with the purpose of developing a detection system for this adjuvant component. SL-Ficolls with polysucrose backbones of 400 kDa (SL-Ficoll400) or 22 kDa (SL-Ficoll22) were not immunogenic. However, SL-Ficoll22 conjugated to bovine serum albumin (SL-Ficoll22-BSA) induced high levels of specific antibodies against SL-Ficoll in mice as determined by an indirect ELISA with either SL-Ficoll400 or SL-Ficoll22 as coating antigen. The specificity of the antibodies was analysed further in a blocking ELISA with SL-Ficoll400 as coat. Dose-dependent inhibition of the ELISA titre was obtained with SL-Ficoll22 and SL-Ficoll400 and the concentration causing 50% inhibition (IC50) was < 1 microg/ml. Non-derivatised polysucrose (Ficoll400) and compounds lacking either lipid or sulphate were not recognised (IC50 > 1000 microg/ml). The reaction of SL-Ficoll400-derivatives with antibodies increased with increasing sulphate and lipid content and maximal inhibition was produced by compounds with a composition similar to the SL-Ficoll22 used for immunisation. Quantitative analysis of SL-Ficoll400 in adjuvant formulations comprising SL-Ficoll400 incorporated in a squalane-in-water emulsion revealed high recovery and sufficient precision. From these data, we conclude that specific antibodies are generated against the synthetic SL-Ficoll400 and that this component of a novel adjuvant formulation can be quantified by an immunoassay.
authors.affiliation: Solvay Research and Technology, Applied Immunology, Brussels, Belgium. 1.a.t.hilgers@id.do.nl
authors.forename: L A
authors.initials: LA
authors.lastname: Hilgers
authors.forename: M
authors.initials: M
authors.lastname: Fochesato
authors.forename: I
authors.initials: I
authors.lastname: Nicolas
authors.forename: G
authors.initials: G
authors.lastname: Lejeune
authors.forename: B
authors.initials: B
authors.lastname: Boon
mesh_terms: D000276:Adjuvants, Immunologic / Q000032:analysis*; D000818:Animals; D001667:Binding, Competitive; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D018796:Immunoconjugates; D008070:Lipopolysaccharides / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D013045:Species Specificity; D014611:Vaccination
chemical_list: D000276:Adjuvants, Immunologic; D018796:Immunoconjugates; D008070:Lipopolysaccharides