Stimulation of lymphocyte proliferation by oyster glycogen sulfated at C-6 position

► The oyster glycogen structure was elucidated. ► Sulfated glycogen SOG that sulfate substitution at C-6 position was prepared. ► Another sulfated glycogen SOG1 with sulfate substituent at C-2 and C-3 was prepared. ► Stronger bioactivity with C-6 sulfate substitution was reported.