Sulfated homopolysaccharides with immunomodulating activities are more potent anti-HTLV-III agents than sulfated heteropolysaccharides.

We reported previously that homopolysaccharides with sulfate groups revealed immunomodulating activities--lymphocyte mitogens. We further investigated the role of homopolysaccharides in a different system--cultivation of Molt-4. clone no.8 with supernatant from human T cell lymphotropic virus type III (HTLV-III)-infected TALL-1, utilizing cytopathic effects (CPE), fluorescence antibody technique (FAT), reverse transcriptase (RT) assay and cell proliferation assay. Sulfated homopolysaccharides such as fucoidan, dextran sulfate with three different molecular weights, cellulose sulfate and k-carrageenan showed most potent anti-HTLV-III activities at mitogenic doses. However, neutral homopolysaccharides had no effects on anti-HTLV-III activities Sulfated heteropolysaccharides such a heparin and heparan sulfate had a little effect on anti-HTLV-III activities. It is suggested that sulfate group is most important in inhibiting growth of HTLV-III, but the structure of the polysaccharides is also important, because homopolysaccharides are more potent anti-HTLV-III agents than heteropolysaccharides.