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.

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-ac etyl-beta-D-glucopyranosyl)-3,6-dithio-beta-D-glucopyranosyl]-3-thio-bet a-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.