Trypanosoma gambiense: antigens involved in phagocytosis.

Abstract Antiserums against trypanosomes were applied and an analysis was made of trypanosome antigens involved in immune binding to mammalian host macrophages. Identified were the antigens which participate in the reaction, the variant clone-specific antigens which are located on the cell surfaces, and those present in the plasma of infected animals with trypanosomes (exoantigens). Variant clone-specific antigens were sensitized for binding to macrophages only by antiserum against the homologous antigenic type. Consequently, binding was noted with clone organisms bearing antigens combined with the antibodies. This was followed by ingestion. When trypanosomes of variant clone populations were also treated with the antiserum against the exoantigen appearing in the clone-infected mouse plasma, the binding of the organisms to macrophages did occur, followed by phagocytosis. No antigens common to distinct variant clone populations were shown to be involved in the binding reactions.