Effect of immunoglobulin M from normal human serum on Leishmania donovani promastigote agglutination, complement-mediated killing, and phagocytosis by human monocytes

Abstract

Serum from healthy, nonimmune humans contained immunoglobulin M (IgM) antibodies that agglutinated Leishmania donovani promastigotes, activated complement, and enhanced promastigote ingestion by human monocytes. The findings indicate that IgM antibodies have the capacity to affect the initial interaction of L. donovani promastigotes with human host defenses.