Macrophage Activation by the Polysaccharide Arabinogalactan Isolated From Plant Cell Cultures of Echinacea purpurea

Abstract

In this study, acidic arabinogalactan, a highly purified polysaccharide from plant cell cultures of Echinacea purpurea, with a molecular weight of 75, 000, was effective in activating macrophages to cytotoxicity against tumor cells and micro-organisms (Leishmania enriettii). Furthermore, this polysaccharide induced macrophages to produce tumor necrosis factor (TNF-α), interleukin-1 (IL-1), and interferon-β₂. Arabinogalactan did not activate. B cells and did not induce T cells to produce interleukin-2, interferon-β₂, or interferon-γ, but it did induce a slight increase in T-cell proliferation. When injected ip, this agent stimulated macrophages, a finding that may have therapeutic implications in the defense against tumors and infectious diseases. [J Natl Cancer Inst 81: 669–675, 1989]