Synthesis of the HSA-conjugate of the S-linked thiomimetic of the branched tetrasaccharide repeating unit of the immunostimulant polysaccharide, schizophyllan. Evaluation as potential immunomodulator

Abstract The conjugate with human serum albumin (HSA) of the S -linked thioanalogue of the branched tetrasaccharide repeating unit of the polysaccharide, schizophyllan, was synthesized from 1,2,4,6-tetra- O -acetyl-3- S -[2,4-di- O -acetyl-3,6-di- S -(2,3,4,6-tetra- O -acetyl-β- d -glucopyranosyl)-3,6-dithio-β- d -glucopyranosyl]-3-thio-β- d -glucopyranose [M.O. Contour-Galcera et al., Carbohydr. Res. , 281 (1996) 119–128] in five steps, and its potential immunomodulatory activity was evaluated in human blood mononuclear cells. The protein glycoconjugate did not effect proliferation or production of IL-4, IL-5 and IFN-g in a significant way.