Modulation of in vitro human lymphocyte responses by an exopolysaccharide from Capnocytophaga ochracea

An exopolysaccharide (EP), purified from spent culture fluid previously inoculated with Capnocytophaga ochracea strain 25, suppressed in vitro human peripheral blood lymphocyte responses to the mitogen concanavalin A. EP was suppressive when added to cultures before the mitogen, but enhanced responses when added 24 or 48 hr after the mitogen.