Dextran induces changes in immunological responses to unrelated antigenic and haptenic stimuli.

Clinical grade, low molecular weight dextran administered intravenously to guinea-pigs altered the course of immunological events that follow unrelated antigenic and haptenic stimuli. Delayed hypersensitivity detectable by dermal responses was initially postponed and upon later retesting was greatly heightened. In addition, the synthesis of circulating antibody that mediates passive cutaneous anaphylaxis was depressed. Infusion of dextran into guinea-pigs with established immunological responses did not alter either delayed hypersensitivity or PCA antibody synthesis.