ENTAMOEBA-HISTOLYTICA - MECHANISM OF SURFACE-RECEPTOR

Binding of antibodies to the surface of the parasitic protozoan Entamo eba histolytica induces capping and release of antigen-antibody comple xes, in a process that may be an effective means of evading the host i mmune response. To analyze the mechanism of capping in E. histolytica trophozoites, optimal conditions were determined for cap induction by sera from patients with amebic liver abscess, by polyclonal anti-amebi c antibodies, and by concanavalin A. Cocapping of actin and myosin was documented by immunofluorescent staining of capped amebas using phall oidin, monoclonal anti-actin antibodies, and polyclonal anti-myosin an tibodies. Immunoblots confirmed the presence of actin and myosin in is olated caps. These observations demonstrate that amebic cytoskeletal c omponents participate in E. histolytica capping of surface receptors. (C) 1994 Academic Press, Inc.